ezee motor + Phaserunner + 1000W limit obsolete?

Hi,
I ran into this dilema with the new Phaserunner I hooked up to my ezee motor:
Since the Phaserunner works by adjusting the phase-current, and if I set the max value to like 50A, and since my A123 can provide infinite amount of current - is there any more significance to input power limit? (which is dialed by setting a battery current limit).

50A phase current is close to the threshold where over-heating issues would start to occur.
The stock ezee controller (Grinfineons as well), will provide way more than 50A at take-off, or when you stall the motor at very low speeds trying to pedal. That's when you feel the wheel "spins" under you if you apply too much throttle at takeoff with those controllers.
Since they don't limit the phase-current to anything near 50A I understand why it's important to set a battery current limit, but then you can easily fry your motor at low speeds. (or if you pick a grinfineon 40A for example)

If I limit to 50A phase current, I have no more takeoff "spins" and no more takeoff over-torque peaks to the fragile gears. In fact, I have no more issues at all!
In my configuration I have a front 9C+ 2706 motor and a rear ezee250rc motor, and they are always working together when going uphill. My battery is 24S A123 at 79.2V, and I let the phaserunner running the ezee to draw a max of 25A battery current. That's 2000W - twice then the stock controller.
That's where I come to think - going uphill consuming 50A phase current with the ezee at 30Km/h I see on the CA 1000W of battery power, but on 50Km/h I see 2000W battery power because of the double back EMF. The battery current would have to be higher, but the phase current would still be limited to 50A. (please negate any difference in torque for the different speeds - remember there is another motor working in tandem).
On the other hand, full throttle on take-off is still just 50A of phase current, but then the battery current yields a very small power like 300-400W or so. (because of zero back-EMF).
You get my drift?
Shall I be still limiting my input power to 1000W (Grin-tech says warranty is void above 1000W)? Because I actually see how with the phaserunner the ezee would live much happier and longer than with the stock controller, and the input power limit is a total bulshit since the PhaseRunner doesn't care at all about your speed. (as long as the battery voltage is still high enough from the back-EMF).
The ezee doesn't care at all on the incoming input power, since at high speeds it provides a really high back EMF that requires compensating higher battery currents - so the ezee just care what is it's phase current. Nothing more! At any speed!

What is your opinion?
Please - ignore any other limitations like the high eddie losses at high speeds. I know going at 50Km/h with an ezee motor has it's draws. I am only asking from electric power perspective, and from the motor's perspective only. I am aware 2000W vs 1000W of incoming power affects the heat build up inside the Phaserunner - but that little thing has a very efficient temperature rollback, just in case.
Roy

Grin's warranty excludes damage caused by overheating. They're not monitoring your power levels, but you can't send in a motor with the winding insulation burned off. They recommend power levels to avoid overheating issues, but these are continuous levels, and the warranty page specifically says "Higher power levels can work fine for short time periods, but in sustained use the above problems will show up."

So at startup, you can dump in a lot of amps, accelerating quickly and briefly heating the motor, because after a few seconds you'll back off and the motor can cool again. But climbing a hill at 50 km/h is a different matter. If you sustain 2 kW, assuming 80% peak efficiency, you're putting 400 W of heat into the motor. And most of the time you're not operating at peak efficiency. If you can't shed that heat effectively, and the hill is long enough, the temperature will eventually be high enough to do damage.

It's not correct that the EZee only cares about motor current, regardless of speed. Any chance you'd reconsider allowing discussion of eddy current?

cycborg said:

Grin's warranty excludes damage caused by overheating. They're not monitoring your power levels, but you can't send in a motor with the winding insulation burned off. They recommend power levels to avoid overheating issues, but these are continuous levels, and the warranty page specifically says "Higher power levels can work fine for short time periods, but in sustained use the above problems will show up."

So at startup, you can dump in a lot of amps, accelerating quickly and briefly heating the motor, because after a few seconds you'll back off and the motor can cool again. But climbing a hill at 50 km/h is a different matter. If you sustain 2 kW, assuming 80% peak efficiency, you're putting 400 W of heat into the motor. And most of the time you're not operating at peak efficiency. If you can't shed that heat effectively, and the hill is long enough, the temperature will eventually be high enough to do damage.

It's not correct that the EZee only cares about motor current, regardless of speed. Any chance you'd reconsider allowing discussion of eddy current?

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At startup, the stock controller dumps in lots of phase amps, which is a high torque, which is a stress for gears (and some wear). Such stress is immediate wear and doesn't depend on accumulating heat. Over long time, that wear will become significant. At least in the way I see it.
The PhaseRunner on the other hand - would not let you push in more than 50A of phase current no matter what (in my own programmed setup), and indeed - the startup is quite sluggish if I just rely on the ezee alone.
Remember that in my setup there is a second front motor that shares the load, so the takeoff is still very impressive and very safe without any wheels skidding.
If the ezee would have worked alone, of course I would have needed way more than 50A of phase current to sustain climb at 50km/h - but in my setup it's able to move it's "work point" to the 50km/h mark together with another motor compared to the 30km/h or less if it did that all my itself. (Same 50A phase current limitation)
I don't see how heat buildup is different at 30km/h vs 50km/h assuming the same 50A of phase current. Wind cooling is not much different between those two speeds.
However, the input power (battery side) at 50km/h is way greater due to the bigger back EMF the controller has to "fight", and therefore consume more battery currents.
It's the same for explaining why a high-turn count motor is not more "torquey" than a low-turn count one of the same model. (for the same copper mass!)
You see my point of view?

And yes, let's talk about eddie losses
If I do assumption according to the specs of the ezee on the Grin page, the magnetic heat losses (due to hysteresis and eddie) are still less than 100W even at high speeds, while the copper loss can be ~400W as you said. Do you think it's more than that?
The eddie losses are lineary increasing with speed, and so the power-loss develops quadruply with the speed.
I also heard a rumour that beyond a certain speed point, the losses will stop rise linearly and go exponentially - and that's where you don't want to be! Is it true?

The power from the battery gets transformed into three different forms in the motor: resistive heating, magnetic heating, and mechanical power. At a constant motor current, the first of these is constant, but the last two increase with speed, which is why the power from the battery increases with speed.

The numbers depend on specific operating conditions, but at a steady-state operating point, the magnetic losses will be comparable in magnitude to the resistive losses. In your example, it's a factor of 3 (100 magnetic + 300 resistive = 400), which probably represents the more heavily loaded end of the spectrum (i.e. a higher ratio of torque to RPM).

The exponential increase you mention may be referring to magnetic saturation - the relationship of torque to motor current starts out linear, but levels out the higher you go. The magnetic material can only support some finite magnetic field strength, so beyond a certain point, to gain an increment of field strength, you need to supply larger and larger increments of current, which of course means more heating. Eventually you can put more and more current in but the magnetic field (and therefore torque) can no longer increase at all, so all of that current and heat is just wasted.

Anyway, I can't say for sure what the practical upshot of this is for you; without a way to monitor motor temperature you can't be sure what's going on in there. I'd say it's best to respect the 1 kW limit for sustained operation, although you could probably safely double this over intervals of, say, 10-100 s.

I still think the magnetic losses are negligible compared with the I2R losses in our discussion.
And I still disagree from a pure physic perspective:
The mechanical load you talk about, is what causing the majority of input power.
Since the motor is always giving a fixed maximum phase current (and torque), without relation to speed, I just don't see how battery current*battery voltage has anything to do with it.
If I WOT (wide open throttle) at stand-still, I get a very small input power in the order of few hundred watts, since the phase current is limited - but because of lack of back EMF, not much battery current is required.
Moving the "work point" to higher speeds, with assistance of the front motor, the same phase current require a much higher battery current due to the back EMF.
Since mechanical power = Torque * Angular velocity - then at higher speeds the motor can deliver higher output powers at the same torque (which is the phase current), since it gets help from another motor.
That's why our motors are so big compared to the RC motor world...

I don't have a temperature sensor inside the ezee, but touching it after operating at 1500W-2000W (with low phase current limit but at high speeds thanks to the help of the second motor), it's feels barely warm to the touch, so I guess my theory is right...
And I still think that the stock ezee controller way higher phase currents at startup, can put way more damage to the gears over time.

No one else knows?

The phaserunner is a fairly new product, with few postings about it. The phase-current control of this controller is also fairly uncommon. I am looking forward to more discussion and data to be posted about it, but...consider yourself a pioneer with a product that looks like it will have a very bright future.

Interesting, you are doing just about the opposite of what I'm doing with the Bonanza, dual PhaseRunners with 9C and BMC, but I've got the 9C in the rear and the BMC in the front.

What's the resistance of your GearMotor? Phase current squared times motor resistance gives resistive loss, is that a level you are comfortable with? Normally the phase current limits low speed heating in the motor, but only temporarily as the speed increases the battery limit takes over. If it is allowed to run 50A of motor current all the time, what will the resulting motor temperature be?

My vendor recommended 1300W and I've chosen 45A of phase current max for the V3/4TT BMC "torque wind" at the moment. I'm running 72V because both of my motors are "torque wind" which means they need high voltage low current, which is well suited to the PhaseRunner's modest current limits.

As you have discovered, the PhaseRunner is very gentle on the gearmotor, especially since I doubled the ramp time on that motor from stock, and kept the stock ramp rate on the 9C. I never hear the clutch engage. The only thing I hear is the BMC front wheel trying to break traction, which it generally does not do. On those rare occasions it has broken traction it doesn't spin up and remains very controllable.

The real question is at what temperature will your gearmotor operate. If the temperature becomes elevated the gears will be quickly destroyed by the high torque. Most of the experience with gearmotor failures has been with the poorly regulated trap controllers with high heat and torque peaks, and the gentler FOC controllers may not suffer as much. So we don't have a lot of equivalent data to draw from.

Since my gearmotor is in the front wheel, and it doesn't have the weight and traction of the rear, I have little interest in pushing it as spinning front wheels are hard to control. I've been considering dropping it to 1kw, at least until I have a knob to adjust torque on the fly. I've tested as high as 1500W on the front wheel on pavement so far. I'm putting more power into the rear DD motor, at the moment 1/3 front gearmotor and 2/3 rear DD motor.

I really think you're getting too caught up in the details. Don't worry about motor vs. battery current, back EMF, and eddy currents. If you're running at a given power level, and your motor is operating at a given efficiency, then you're generating an amount of heat that is uniquely determined by these two numbers. And neither of these is substantially improved by using the PhaseRunner. Your power is what your wrist tells it to be, and your efficiency may be slightly better due to sinewave, but if you'd overheat in 5 minutes, this might stretch it to 8-10 minutes, but you won't be able to run indefinitely.

The advantages of the PhaseRunner lie elsewhere. Smoother startup protects the gears (among other things). You have more intuitive control over acceleration and regen. You can use field weakening to go beyond your motor's Kv limit. You have more options for customization.

A controller can't make power limits obsolete. For that, you need superconducting windings and magnetic materials with no hysteresis or electrical conductivity. Until that motor becomes available, you'll need to balance heat generation with heat dissipation.

Alan B said:

Interesting, you are doing just about the opposite of what I'm doing with the Bonanza, dual PhaseRunners with 9C and BMC, but I've got the 9C in the rear and the BMC in the front.

What's the resistance of your GearMotor? Phase current squared times motor resistance gives resistive loss, is that a level you are comfortable with? Normally the phase current limits low speed heating in the motor, but only temporarily as the speed increases the battery limit takes over. If it is allowed to run 50A of motor current all the time, what will the resulting motor temperature be?

My vendor recommended 1300W and I've chosen 45A of phase current max for the V3/4TT BMC "torque wind" at the moment. I'm running 72V because both of my motors are "torque wind" which means they need high voltage low current, which is well suited to the PhaseRunner's modest current limits.

As you have discovered, the PhaseRunner is very gentle on the gearmotor, especially since I doubled the ramp time on that motor from stock, and kept the stock ramp rate on the 9C. I never hear the clutch engage. The only thing I hear is the BMC front wheel trying to break traction, which it generally does not do. On those rare occasions it has broken traction it doesn't spin up and remains very controllable.

The real question is at what temperature will your gearmotor operate. If the temperature becomes elevated the gears will be quickly destroyed by the high torque. Most of the experience with gearmotor failures has been with the poorly regulated trap controllers with high heat and torque peaks, and the gentler FOC controllers may not suffer as much. So we don't have a lot of equivalent data to draw from.

Since my gearmotor is in the front wheel, and it doesn't have the weight and traction of the rear, I have little interest in pushing it as spinning front wheels are hard to control. I've been considering dropping it to 1kw, at least until I have a knob to adjust torque on the fly. I've tested as high as 1500W on the front wheel on pavement so far. I'm putting more power into the rear DD motor, at the moment 1/3 front gearmotor and 2/3 rear DD motor.

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Guys, you all misunderstand my question! I know overheating on short period, or moderate heat on long period will damage the gears and/or melt the windings.
That's not my question.
I ask from a pure physic point of view:
Thanks to the phaserunner and the help of the front 9C+ 2706, I am able to apply those same 50A phase current at high speeds - which by the law of physics indicate a much higher mechanical power output (and hency a much higher input battery power). I even tried 40A current limit, which even at Justin's simulator doesn't overheat at all (as if the motor is at standstill and not rotating), and still - at high climbing speeds - my input power will well exceed the 1000W stock recommendation. The motor is able to do more physical work (transfering the same torque but at high speed), and therefore the input battery current increases.
Yet, it doesn't overheat, at all! I even touched it to check - and it was not even barely warm.
This is over course only possible because there is another motor which shares the load. I moved the workpoint of both motors to much higher speeds. They still operate without the slightest overheat.
Both motors are able to convert electric power to mechanical power better at high speeds, if you limit your phase current wisely. Assuming a constant 40A phase current, your I2R losses (and the main cause for efficiency loss) are fixed, all the time!

A stock controller, on the other hand, would start to limit your input power at high speeds so your phase current will drop - which is quite pointless unless you have a certain current limit you don't want to stress the battery with, but that's not our topic for today.
At very slow speeds, on the other hand, the stock controller doesn't care about phasecurrent at all! Try Justin simulator and see for yourself. THESE conditions, in my opinion, are the ones which responsible for the wearing of the gears over time. Heat has a much less impact, unless of course you overheat the motor seriously.

And regarding the ezee's resistance, here is the spec page:
http://www.ebikes.ca/shop/ebike-parts/motors/mezee250rc.html
It's 0.055Ohm. 40*40*0.055 = 88W of copper heat. That's all! And as I said, it will be the same loss at any speed unless you "let go" of the throttle to less to 100%.
Even 50A yields just 137.5W of copper heat, and that's already a point where on simulator you will have overheating issues, but only for very long time AND if there was no wind cooling. (motor wasn't spinning)

Guys, you all misunderstand my question!

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OK, try restating it. I thought you were going to do that but then there were many many words and none of these -> ?

Let's look at this in a different way.

The efficiency improvement from running two motors is not related to the controller. It would happen with any controller.

You have doubled the heat dissipation capacity of the system by adding a second motor and controller, and reduced the torque demands of each motor.

Let's look at it in more detail:

To develop the same total torque, half the motor current is required in each motor.

So look at one motor and one controller. Heat in both is mostly related to motor current. Heat is mainly from I squared R. R hasn't changed, but I is half. I squared is now one quarter of the single motor case. So the motor runs cooler.

Note that Justin's simulator ignores phase current limits, and therefore is not representative of heating and torque at low current where your controller will reduce PWM to control phase currents.

Where the PhaseRunner will extend the life of gearmotors is by restricting those high torque events and sudden clutch activations that occur with trap controllers. Note that trap controllers don't have to behave this way, they just happen to not handle these conditions carefully enough. Features like block time ignoring high phase currents, and too-short ramping (which is a result of customers wanting immediate torque) are very hard on gearmotors and can break them, especially if the motor is hot and the gears soft. Sine controllers tend to have more sophisticated software that avoids these sudden current changes.

Alan B said:

Let's look at this in a different way.

The efficiency improvement from running two motors is not related to the controller. It would happen with any controller.

You have doubled the heat dissipation capacity of the system by adding a second motor and controller, and reduced the torque demands of each motor.

Let's look at it in more detail:

To develop the same total torque, half the motor current is required in each motor.

So look at one motor and one controller. Heat in both is mostly related to motor current. Heat is mainly from I squared R. R hasn't changed, but I is half. I squared is now one quarter of the single motor case. So the motor runs cooler.

Note that Justin's simulator ignores phase current limits, and therefore is not representative of heating and torque at low current where your controller will reduce PWM to control phase currents.

Where the PhaseRunner will extend the life of gearmotors is by restricting those high torque events and sudden clutch activations that occur with trap controllers. Note that trap controllers don't have to behave this way, they just happen to not handle these conditions carefully enough. Features like block time ignoring high phase currents, and too-short ramping (which is a result of customers wanting immediate torque) are very hard on gearmotors and can break them, especially if the motor is hot and the gears soft. Sine controllers tend to have more sophisticated software that avoids these sudden current changes.

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The fact I have two motors is just like comparing a strong tail wind or light weight bicycle with a single motor.
The two motors can draw together powers around 4KW, more than their rated stock power combined, and still don't overheat at all. It's not that I halved the 1000W input power between two motors. That's only because they are both still delivering their rated torque but at much higher speed - hence higher mechanical power and the source of this discussion
You can imagine the ezee gear alone propelling you on a flat with a 72V pack, and using a 29er wheel - As long as you limit the phase current to around 40A, you will drive at 55Kph, drawing almost 2000W from the battery. Overheat? Nothing! Try it yourself in the simulator, and note what is the phase current at that setting.
Now after converting to Phaserunner, I really don't understand how anyone would still use a trapezoid-controller, especially if they have a geared motor - it's a death sentence, that eventually will eventually be more expensive after you replace your gears and/or the motor. Really...

If they were still delivering the same single motor torque, they would be as hot as the single motor. The fact that they are not hot means directly they are not delivering the same torque.

One way to think of it is that Torque squared (times some constant) is motor heat.

Torque is what limits the motor performance, not power. The motor doesn't care about power, only torque. The motor sees motor (phase) current which makes heat and magnetic fields which make torque. The speed (RPM) makes back EMF which reduces the voltage from the controller, and the remaining voltage across the motor resistance determines the current. The system accelerates or decelerates until it is in equilibrium, as all systems tend to do.

Another way to think of it is torque determines speed. If dual motors are going faster, they are farther up the curve, allowed to go there because the torque required by two motors is lower. The motors are dividing the torque required to propel the bike. They each have only half a bike to propel, hence they rise up the curve to a higher speed. The power is higher but the individual torque is lower than the torque required of a single motor.

If you shut one motor down it doubles the torque load on the remaining motor, and the bike will slow until it finds a new equilibrium at a lower speed and higher torque for the one motor, and it will dissipate more power as heat from the higher torque loading. Then you re-engage the second motor and the torque load splits again, so both motors have more excess torque to accelerate with, and they find a new equilibrium where each motor outputs a torque which is now greater than half but less than double of the single motor situation.

The PhaseRunner is a great controller, but it has almost nothing to do with your results. Two trap controllers would achieve nearly exactly the same result.

Alan B said:

If they were still delivering the same single motor torque, they would be as hot as the single motor. The fact that they are not hot means directly they are not delivering the same torque.

One way to think of it is that Torque squared (times some constant) is motor heat.

Torque is what limits the motor performance, not power. The motor doesn't care about power, only torque. The motor sees motor (phase) current which makes heat and magnetic fields which make torque. The speed (RPM) makes back EMF which reduces the voltage from the controller, and the remaining voltage across the motor resistance determines the current. The system accelerates or decelerates until it is in equilibrium, as all systems tend to do.

Another way to think of it is torque determines speed. If dual motors are going faster, they are farther up the curve, allowed to go there because the torque required by two motors is lower. The motors are dividing the torque required to propel the bike. They each have only half a bike to propel, hence they rise up the curve to a higher speed. The power is higher but the individual torque is lower than the torque required of a single motor.

If you shut one motor down it doubles the torque load on the remaining motor, and the bike will slow until it finds a new equilibrium at a lower speed and higher torque for the one motor, and it will dissipate more power as heat from the higher torque loading. Then you re-engage the second motor and the torque load splits again, so both motors have more excess torque to accelerate with, and they find a new equilibrium where each motor outputs a torque which is now greater than half but less than double of the single motor situation.

The PhaseRunner is a great controller, but it has almost nothing to do with your results. Two trap controllers would achieve nearly exactly the same result.

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Hi, you are absolutely correct. I am aware that if I had a single motor and applied the same phase current limitations, I would have had to pedal with the bike while going uphill. Still - on flats - one motor with the same limit would have been enough, and still it would allow much higher speeds with a phaserunner since I won't be battery-input-current limited anymore. (I will find it stupid to limit to 1000W on flat, just because the mechanical power is high and the torque required is low)
I tried with trap-controllers, and I find it very hard to control both motors and their torques, since regular trap controllers convert your throttle to speed, not torque. So the result would have been similar, yes, but still the two motors would heat up more because there won't be any phase current limit at takeoffs. During uphills, you can't control how much phase current is going into a motor since the CA "sees" only the incoming power/current, which as we shown doesn't correlate directly to motor heat.
With the two phase runners I can fully twist my two throttles at takeoffs, get a nice and smooth acceleration, and be sure no gear damage can ever occur. Same for uphills.

The PhaseRunners are definitely easier to balance for dual motor setups. Torque throttle inputs reduce sensitivity to throttle changes and compensate for unequal motor Kv while FOC measuring and smoothly controlling the actual motor phase current instead of attempting to mathematically predict it in the controller, plus the built in ramping that smooths out the transitions absorbs some of the acceleration jerking that people "like" but is hard on the equipment. So the PhaseRunners are smooth and more accurate at limiting phase current.

The better (programmable) trap controllers do have phase limit adjustments, the CA cannot do that but you can program a Lyen controller, for instance, to have a phase current limit and a battery current limit (and if you set the battery current limit to 70-100% of the phase current limit then the battery current is effectively unlimited). During the (even the minimum) block time the trap controllers just don't bother to enforce the limit which can be a problem, if the system resistance is very low the peak currents can be too high. On the Borg I made a low resistance and low inductance wiring setup with a 24 FET controller, no BMS, 18S4P of Turnigy 25C Lipo, short series-parallel hydraulically crimped multiple conductor paired wiring harness, etc, and had failures from time to time as the peak currents during block time with a cold motor and controller hitting a 15% gradient were difficult for the imperfectly balanced FETs to manage. The Sabvoton fixed all that in a similar way to the PhaseRunners, with actual monitoring and smooth control of the phase currents and avoidance of the extreme peaks.

The issues of max speed and power with geared hubmotors remains, they operate at much higher RPM so you may start to see dynamic losses that generate significant heating (at higher power/back EMF/speed), and with low voltage (speed winding) type motors and a high voltage battery the controller may be able to sustain the max phase currents to much higher speeds producing enough heat in the motor to soften the gears and allow torque to damage them. While the motor failures and warranty settings were designed for the trap controller experience and may be somewhat incorrect for the suave sinewave control, it may not be correct to feed these motors with effectively unlimited power unless you have deep temperature sensors in the motor that are used to limit power as the temperature rises, with the appropriate but hard to know derating curves. When the motor is hot the torque handling capacity is reduced, the the phase current limits are not correct continuous limits unless you set them uncharacteristically low. For example a cold motor may be able to handle 80 amp bursts but a hot one may only be able to handle 30 amps maximum, and if the phase current limit is 50 amps, one day when conditions happen to combine and heat up the motor it will not survive. So setting the maximums is not simple, and limiting the power by setting the battery current low forces the phase current maximum currents to be short term rather than continuous limits. Ilia, expert geared motor vendor, recommended that I shut down the BMC at higher speeds, partly for traction concerns as it is a front wheel motor, and perhaps partly due to the high voltage being capable of sustaining high phase current levels and overheating the gearmotor at high speeds. We talked about an internal temperature sensor but the dual phase wires have filled the passage leaving no space for additional temperature probe wiring.

The fact that your motors operate cooler with 2WD under normal conditions doesn't mean they will never get hot, the right combination of ambient temperatures and steep gradients combined with on-gradient starts may one day warm them up and result in a condition where hot gears and high torque cause a failure. Even limiting the power is a rough approximation when conditions change.

I don't have a temperature sensor in either motor, but it would be interesting to plot temperature of both motors at high speed and see if under any conditions the gearmotor begins to build up heat. The internal heatflow path is very poor, and combined with the high RPM and high continuous phase current the dynamic losses might cause considerable heating at higher speeds that could be easily measured.

In summary, I don't plan to supply unlimited power to the gearmotor, to keep the system reliable I have set max power (by battery current limit) to around 1300W and will instead allow power in the DD motor to go higher. In my case the DD motor's high voltage (high turn count) windings need a bit of field weakening to "keep up" with the geared motor so the extra current is going to good use.

I do see the power in the gearmotor dropping off as I hit max speed, the field weakening is working and the DD motor is exceeding the speed of the higher Kv gearmotor. I could program the max speed on the gearmotor and drop it out completely (as Ilia recommends) as it is not contributing when the speed gets high enough anyway, based on the current and power readings, and the DD motor is carrying the whole load at that point. That is not the case on a gradient, as the DD motor doesn't have enough torque at high speeds to handle the work of climbing (and the geared motor is supplying extra torque for climbing), but when in level (or slightly downhill) flight it can sustain higher speed with field weakening as the torque required is lower than steep climbing requires.

It is all a learning experiment, and I'm just getting started to watch the dual CA instrumentation and characterize the behavior. Each setup will be somewhat different with motor Kvs, voltages, and settings as well as ambient temperatures and speed/gradient combinations. If you continue to push the geared hub RPM and power and measure the temperature you may explore that envelope in a different way than the trap controllers already have. Many times I have seen a new geared motor owner exclaim "this motor handles 2000W or 2500W" or whatever, only some time later to hear that their setup failed. Defining a Safe Operating Area is a complex process, and frequently there are corners in the allowed operational area that are in fact not safe, they just aren't easy to explore, and one day they may be entered and found to result in a failure.

what the max power anyone got out of the phase runner contollers ?

I've seen about 3kw on my setup.

The theoretical max is around 80V times around 50 amps (4KW) if you have a really excellent heatsink, one user said he was unable to get more than 43A actual even when set higher. It depends on the motor characteristics, and whether the phase current limit is reached first, or the back EMF limits the current before the battery current limit is reached. This is excellent for a six FET controller.

thunderstorm80 said:

Hi,
Shall I be still limiting my input power to 1000W (Grin-tech says warranty is void above 1000W)? Because I actually see how with the phaserunner the ezee would live much happier and longer than with the stock controller, and the input power limit is a total bulshit since the PhaseRunner doesn't care at all about your speed. (as long as the battery voltage is still high enough from the back-EMF).

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Hey Roy, you are exactly correct here in all of your reasoning, and there is no reason that you couldn't have both a 50A phase and 50A battery current limit on the Phaserunner and run the eZee motor at upwards of 2500 watts when you are moving fast with a 50V battery pack. This will be less thermally stressfull on the motor than putting in say 1000 watts at a low speed when your actual phase current might be more like 70+ amps and the effect of passing air cooling is reduced. So yes, saying that a motor has an "input power limit" is BS, which is why we generally do everything we can to avoid talking about motor or controller power ratings or power limits.

On the other hand, trying to explain that to every person who asks us "how many watts can this motor take?" is super onerous. I try my best and attempt to educate people over email on this topic many times a week, yet at the end of the day most people don't want a lecture in thermodynamics and physics they just want a number they can compare with someone else's number.

Please - ignore any other limitations like the high eddie losses at high speeds. I know going at 50Km/h with an ezee motor has it's draws. I am only asking from electric power perspective, and from the motor's perspective only. I am aware 2000W vs 1000W of incoming power affects the heat build up inside the Phaserunner

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Again, not necessarily, as the phaserunner like the motor is mostly heated from I^2R on the phase current, so the same conditions that can cause the motor to heat up faster with 1000 watts at slow speeds than 2000 watts at high speeds will be mirrored in the controller too.

Whether mechanically the gears inside the motor are just as happy with a high torque at a high RPM versus a high torque at a low RPM, I can only speculate. I don't have any data one way or another there.

justin_le said:

thunderstorm80 said:

Hi,
Shall I be still limiting my input power to 1000W (Grin-tech says warranty is void above 1000W)? Because I actually see how with the phaserunner the ezee would live much happier and longer than with the stock controller, and the input power limit is a total bulshit since the PhaseRunner doesn't care at all about your speed. (as long as the battery voltage is still high enough from the back-EMF).

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Hey Roy, you are exactly correct here in all of your reasoning, and there is no reason that you couldn't have both a 50A phase and 50A battery current limit on the Phaserunner and run the eZee motor at upwards of 2500 watts when you are moving fast with a 50V battery pack. This will be less thermally stressfull on the motor than putting in say 1000 watts at a low speed when your actual phase current might be more like 70+ amps and the effect of passing air cooling is reduced. So yes, saying that a motor has an "input power limit" is BS, which is why we generally do everything we can to avoid talking about motor or controller power ratings or power limits.

On the other hand, trying to explain that to every person who asks us "how many watts can this motor take?" is super onerous. I try my best and attempt to educate people over email on this topic many times a week, yet at the end of the day most people don't want a lecture in thermodynamics and physics they just want a number they can compare with someone else's number.

Please - ignore any other limitations like the high eddie losses at high speeds. I know going at 50Km/h with an ezee motor has it's draws. I am only asking from electric power perspective, and from the motor's perspective only. I am aware 2000W vs 1000W of incoming power affects the heat build up inside the Phaserunner

Click to expand...

Again, not necessarily, as the phaserunner like the motor is mostly heated from I^2R on the phase current, so the same conditions that can cause the motor to heat up faster with 1000 watts at slow speeds than 2000 watts at high speeds will be mirrored in the controller too.

Whether mechanically the gears inside the motor are just as happy with a high torque at a high RPM versus a high torque at a low RPM, I can only speculate. I don't have any data one way or another there.

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Wow! Justin! Thanks for commenting on my post and strengthening my opinion regarding phase current vs the useless input power definition.
For a geared motor with limited heat-shedding and fragile gears, limiting the phase-current is so so important!
But let me ask according to what you wrote, Phase-Runner wise: It doesn't heat up only from phase-current being delivered to the motor, but also from the battery current it draws from the battery, isn't it? That is - if you deliver the same output power at a certain work-point, the Phaserunner would heat-up less when feeding from 48V pack than 36V. Correct me if I am wrong. (Assuming you are only phase-current limited, and not battery-current limited or back-emf limited).

And regarding happy gears vs speed: You once told me that there is more mechanical-energy loss on the gears when going at higher speed. I assume, it can come from the friction turning-torque of the planetary gear system, and rises linearly. (It becomes quite apparent by drawn current at high unloaded speeds)
I assume also that the friction-torque will rise linearly with the loaded torque, and therefore the losses are quadrupled with speed.
Maybe someone with a mechanical engineering degree can answer?
I only speculate, and that can solve the riddle whether high speed is an energy waster for geared motors or not.

As Justin already mentioned, the phase current is the dominant heating factor in the motor controller, not the battery current. The phase current is always present, the lesser battery current is only flowing during the PWM-on part of the cycle. Hence phase current (being larger and full-time) dominates the I squared R heating term. A higher voltage battery does not reduce heat in the controller for the same motor torque and current.

A higher voltage battery gives the potential for higher speed as well as higher motor current and torque. In doing this it provides the capability for higher motor and controller heat, if you allow these increases to occur.

Hi all, have been reading this thread with interest as I'm currently building a new 29er bike with ezee 350rpm rear motor and phaserunner controller.

I see that no one seems to have a thermistor on their ezee motor... so here are some pics of my retrofitted thermister.




I wanted the thermister as it gets really hot here in summer (45 deg C), and I'm planning to push the motor a little harder than the basic limits outlined in the specs, so it seems like cheap insurance.

Originally I'd thought to sneak the thermister cables in with the standard cables but there isnt enough room in the original hole, (the guys at ebikes.ca told me this, but I tried anyway and so found out for myself

I brought the cable out the right side of the motor for 2 reasons, 1) it was easier that way! and 2) I didnt want to remove metal from the axle on the side which already has the hole for the other cables.

I started with a v small tungsten cutting bit on the die grinder to make the groove for the cable, but switched to a small v narrow grinding stone as it was faster and easier to control. The final part of the groove where the cable passes 90deg around the armature was the most difficult. For this part I used a 2.5mm boring bit (basically a drill) and made a series of adjacent shallow holes in the shaft and armature, then machined out the remaining space between them to finish the groove. There was already a slot in the armature to bring the cable through, but I deepened it a little to make sure there wouldnt be any clearance issues, then tied the cable down with some copper wire from an old armature winding (copying what ezee do for the main loom). You don't see it in the pics, but I glued the thermister to the windings using epoxy resin, rated to over 250deg.

Total time for the install was about 4 hours, which included dismantling/reassembling the wheel and tyre, so it's not a huge job by any means.

Now for my question for you folks

Ive hit a hurdle getting the phaserunner tuned to the motor using the grin software. The software connects to the phaserunner, and runs the static motor test ok, but fails at the rotating test with the error code "faults [9]: instantaneous phase over current". The motor does turn a little but cuts out abruptly and the LED blinks in the repeating pattern of 2 2 6 7 flashes.

I've tried to change some parameters as per the suggestion in the manual, but no joy. From the little that I've understood, the problem might be related to the sensorless starting parameters, or the feedback bandwidth tuning, but I'm at a loss for what to change/try.

I see some people have this motor running with a phaserunner, so am hoping you could advise???

BTW To rule out a problem with the motor I connected it to my other ride, (Grin 40a controller, 53v battery pack, CAV3, and it spun up normally - phew!).

dean74 said:

Ive hit a hurdle getting the phaserunner tuned to the motor using the grin software. The software connects to the phaserunner, and runs the static motor test ok, but fails at the rotating test with the error code "faults [9]: instantaneous phase over current". The motor does turn a little but cuts out abruptly and the LED blinks in the repeating pattern of 2 2 6 7 flashes.

Click to expand...

A lot of people have had this problem and the best solution seems to be increasing the PLL bandwidth. See this post.

thanks cycborg, problem solved!

I'll put some real temp data up here once I get the bike finished. stay tuned...

Have been meaning to update with my experience on this... which is so far really good.

So i have the Ezee 350rpm motor, Phaserunner, 29in wheel, running 58v (14s lipo) in a carbon mountain bike setup, total weight is a very skinny 18kg!

Phaserunner is configured to 45a battery current limit, 95a phase current limit.

I typically ride at around 50km/hr and my commute to the office is about 10km each way. On my normal commute the motor stays really cool, generally 60-80deg. The phaserunner is mounted to an exposed 6mm aluminium bracket that doubles as a heatsink, so it also stays cool, I dont know the actual temperature, just that it feels warm to the touch, but never hot (so i havent bothered plugging in the software to check - sorry!) See pic.

The longest climb ive made has been about 5km at a 5% gradient, made at about 35-40km/hr, with moderate pedal assist. The motor temp at the end of that climb was in the high 80s (degreeesC).

It took a little time to get the phaserunner working, during which time I understood from the guys at ebikes.ca that while the core temp of the motor is being monitored, and stays cool, I shouldn't have any reliability issues from the electrical system, which just leaves the nylon gears to consider.

IMO the stress on the gears in this system is actually lower than with the original ezee 20a controller as the ezee controller is not phase current limited, and so it actually produces more torque from standstill than the phaserunner does - and this is where the gears will see the highest stress. So i figure if they hold together in a low speed cargo bike, climbing hills with a lot of weight, then they should be fine on my 18kg bike Time will tell I guess.

Performance is all relative ... my other bikes use grin 40a controllers, with similar voltage packs. The only significant difference i can report is that the phaserunner is comparatively sluggish to get off the line, which is no big deal. Once the bike is moving the response is what you'd expect from a 2500w bike.

The torque throttle has good and bad points imo. The good is that you dont need to be so careful with it to get a smooth response which is nice. The bad, is that you need to twist it the whole way around to get full power, which is not ergonomically easy while standing or changing gears.

Of course the other important difference is that the phaserunner is tiny! Which was my main motivation for buying it. I wanted to build a really lightweight clean bike, and the tiny controller helps keep it all compact.

All in all I'm really happy with the outcome. The only thing I'd change would be to use a non geared motor, but then the weight goes up a lot, so until grin make the all axle motor for a rear wheel build, then it will stay like this. I dont like the way the geared motor stops turning when you release the throttle (but are still moving), then needs time to get back to speed before it accelerates again, it makes the motor feel laggy...

hope this is helpful to someone out there