5303 with 20" or 5304 with 24" with delta wye?

[Doctorbass]

I am very confused about this chouce and i request your Help!

I more need your experience than theory this time.

Wich motor to choose??!!

a 5303 on a 20"
or
a 5304 on a 24"

:| it look the same trust and speed!

maybe the advantage of the 20" would be that the wheel is smaller and will allow less wind drag and drop out will suffer less cause of the higher rpm and lower torque?....

I am REEEEEEEEEEEEEEEEEEAAAALLLY confused guys!

I am building a project to reach the max reachable speed on an electric bike with 100V and delta wye setup.

For sure i'll have a 18x 4110 controller but I know that when switching in delta, the phase current will be 1.7 time the original current!

since the 5303 draw more current, it is on a 20" wheel so that should conpensate?.. and the 5304 is on a larger wheel so... they look pretty the same?

I expect 60-65MPH so at full speed it should draw around 6500W continuous... but i need that for 20sec...

HELP !

Doc

 

[michaelplogue]

I would go with a 5304 on a 20" wheel. That way you would have very excellent torque and acceleration in the WYE config, then get the speed boost with the Delta.

At 72V, a 20" 5304 should get up to 30-35 mph. Assuming a 1.7 increase in delta, you would theoretically be able to get up to 50-60 mph

With your 100V setup, you should be able to easily reach your speed goal.

 

[ZapPat]

Higher electrical RPM's means more motor efficiency, so I would go with the 20in too.

 

[Doctorbass]

Thanks Guys!

i'll go with the 20" for two more reason than the 24" on 5304:

the 5303 with 20" make the ebike lower from the ground and will generate less air drag

+ like Zapat said, the 5303 have a better efficiency because it simply run at higher rpm...


and on a 20" wheel at 65mph the rpm of the wheel will be around 1200RPM !!

Doc

 

[huskydave]

5303 is the better choice for speed. It will go 95km/h or more @ 100v.

 

[johnrobholmes]

You will have more power with the 20" setup, as the motor will be spinning faster for the same ground speed.

 

[rkosiorek]

i've got some extra wide (40mm) 20" 36 hole rims that i got from Ypedal. i had them on the 5302 for a while. Ypedal bought these from Zero Electric Motorcyles when they switched to larger diameter wheels.

i used some Pirelli ML75 (2.75-16 46J REINF) motorcycle/scooter tires that fit those rims perfectly. they may be a lot heavier than bike tires, but they are speed rated to run at highway speeds safely. they are also rated for much heavier vehicle loads

the tirese have a higher profile than bicycle tires. the outside diameter is approx 21.5" putting them in the middle etween regular 20" and 24" bike tires. this allows for a touch more gearing without sacrificing all of the top end speed.

i'd go with the 5304, the 20" wide rims and the Pirelli tires. should give very good acceleration and bottom end grunt without loosing much if anything on the top end.

rick

 

[Doctorbass]

i've got some extra wide (40mm) 20" 36 hole rims that i got from Ypedal. i had them on the 5302 for a while. Ypedal bought these from Zero Electric Motorcyles when they switched to larger diameter wheels.

i used some Pirelli ML75 (2.75-16 46J REINF) motorcycle/scooter tires that fit those rims perfectly. they may be a lot heavier than bike tires, but they are speed rated to run at highway speeds safely. they are also rated for much heavier vehicle loads

the tirese have a higher profile than bicycle tires. the outside diameter is approx 21.5" putting them in the middle etween regular 20" and 24" bike tires. this allows for a touch more gearing without sacrificing all of the top end speed.

i'd go with the 5304, the 20" wide rims and the Pirelli tires. should give very good acceleration and bottom end grunt without loosing much if anything on the top end.

rick

Yeah.. the 5304 on 20" only give me 72km/h max at 100V in Star mode... and in delta the true multiplication factor is not 1.7.. but in real life speed gai it's more like 1.5.. so 1.5 x 72 =108km/h... 67mph estimated...

hmmm.. i'm still 50/50 now..

guys.. i've never felt as confused as now about that!.. :|

5404... 5303... 20"... 24"....

Doc

 

[Ypedal]

My vote is on the 5303 in 20"..

Efficiency be damed if the goal is simply top speed.. the no load speed of the 5303 being higher will allow you to pump the amps into it, only limiting factor is heat and at the speed you will be going it will cool down enough for the time you need to run it.

20" wheel has more leverage, smaller wheels are key. You got a capable battery pack that can put the amps requried, so no problem there..

:wink:

 

[karma]

5303 on a 20 high rpms. got my vote.

 

[Doctorbass]

My vote is on the 5303 in 20"..

Efficiency be damed if the goal is simply top speed.. the no load speed of the 5303 being higher will allow you to pump the amps into it, only limiting factor is heat and at the speed you will be going it will cool down enough for the time you need to run it.

20" wheel has more leverage, smaller wheels are key. You got a capable battery pack that can put the amps requried, so no problem there..

:wink:

ok for the 5303! :wink:

"Is that your Final decision sir"?

YES

 

[slayer]

5303 with 20 inch rim and tire from rkosiorek would be my vote.

 

[rkosiorek]

just to give you a look at one of those tires on the 40mm wide rims.





rick

for bonneville use the 5303 or 5302. for the dragstrip i'd try the 5304. especially if it is only 1/8th mile. 1/4 mile you may top end very early in the run and the 5303 may be better. of course wind drag on your body and weight may limit top speed well below that of the calculator. for the record you may want to try and find a fearless 100lb rider. know any pro jockeys?

 

[ZapPat]

My vote is on the 5303 in 20"..

Efficiency be damed if the goal is simply top speed.. the no load speed of the 5303 being higher will allow you to pump the amps into it, only limiting factor is heat and at the speed you will be going it will cool down enough for the time you need to run it.

20" wheel has more leverage, smaller wheels are key. You got a capable battery pack that can put the amps requried, so no problem there..

:wink:

ok for the 5303! :wink:

"Is that your Final decision sir"?

YES

I actually think that you might get more torque with a 5304 instead of a 5303, thus better acceleration also.

I come to this conclusion for one main reason, and without this limitation the 5303 would yield similar acceleration but with a higher top speed. The limiting factor that may be (or may not be) of concern is maximum motor current that the controller will allow, meaning the maximum phase current that the controller will allow before limiting its output. If you do hit this limit which will always happen more at low RPM where the motor's low BEMF can cause very large currents to flow into the motor. To know if you may hit this limit with the 5303 or not, just calculate what peak current can flow using the total system's resistance (cells, BMS, battery wires, FETs, motor wires, motor winding resistance) and the batterie's voltage. You know ohms law and your other parameters here, Doc, so I'll let you check that yourself! Oh, remember when comparing results that the 5304 will produce 33% more torque for the same controller phase current, which is why it would be better to use if you stay in the controller's ouput current limiting zone for very long at low RPMs.

So my vote is a 5304 in a 20in wheel unless your controller is capable of huge output currents.

 

[steveo]

RPM

Is a very good thing .. but when your aiming for top rpm .. I say 5304 or 5305 .. yes its less rpm.. but there is better chance at hitting higher speed because there is more torque to get to the desired speed .. the 5303 could do this as will .. but if the motor can't reach near top rpm .. this could mean bad things for the controller.

5304 in 24 ... or in 20" rim with a higher tire .. maybe around 21" in diameter with rubber.

-steveo

 

[johnrobholmes]

A 5304 would only be faster than a 5303 (ignoring controller and batteries) if the motor gets saturated. The 5303 would just pull more amps to compensate for the kT value difference. A 5304 does not have more torque, only more torque per amp.


The only way to really know the best wind for your voltage and "gearing" is to test it out. You will have a max speed for the motor no matter what wind, it can only push so many watts out before saturation eats into power out like a fat woman at a buffet.

 

[ZapPat]

A 5304 would only be faster than a 5303 (ignoring controller and batteries) if the motor gets saturated. [...] You will have a max speed for the motor no matter what wind, it can only push so many watts out before saturation eats into power out like a fat woman at a buffet.

Did you invert the 5303 and the 5304 in the first sentance here? The rest makes very good sense, and it's a good thing someone mentioned this additionnal limiting factor when these things are pushed to insane levels!

The 5303 would just pull more amps to compensate for the kT value difference. A 5304 does not have more torque, only more torque per amp.

I guess you say this in the light of your above "ignoring controller and batteries", because if the controller does limit it's max phase current in addition to it's max battery current, then you will hit this limiting factor faster with the 5303 than the 5304. This is why I mentioned in my previous post that the 5304 would give an extra 33% torque in this case, since the same phase current on the 5304 happens at a higher phase voltage (33% higher of course). BTW, infinion based controller apparently do have some kind of simple phase current limiting (if we can really on the configuration software). Since there is no actual hardware to measure phase current on the infinion, it is most likely derived from the measured battery current divided by the duty cycle (duty cycle being between 0 and 1 here, representing 0 to 100% output).

Magnetic saturation might well become a problem before the controller's max phase current is reached, but the magnetic saturation point will be exactly the same for both motors as John points out, one will just happen at higher volts and lower amps going in it than the other (ie same watts into the motor in either case). Any ideas of when this might happen with the 530X? It depends on the stator lamination's magnetic retention capabilities I guess, but I wonder if there is a way to aproximate this? I know that if we send in high power pulses and observe the waveform with a scope, the dV/dt slope made by the winding's inductance will change as it reaches saturation. This happens because the motor's inductance changes abruptly when it's core saturates.

 

[Doctorbass]

That's all very interesting guys!.. this thread is becoming very technical and i love it!

I agree with you Zapat about the phase current with a 5303 and a 5304..

I agree with all of you..

let me remind what is important to know here:


- first, The simulator on ebikes.ca reflect the exact conditions i test and it is aan excellent aproximation of the real life test i do!: Ex:when i simulate the same conditions than my actual setup on my mongoose it is very close to the real speef and power i measure!

I use these data: 90V ( i dont use 100V because at 95-100V that's like a floating voltage right after charge.. and the firsts Ah will drop the voltage of the battery to around 95V. So i preffer using 90V because this is a very flat reagiob of my battery and give me a safe margin) 5303, 24" 100A, 0.1ohm battery, 0.01ohm controller 100% throttle.

What i calculate on the simulator is to try to keep 115km/h at max efficiency peak wich represent better the point of the real max speed. ( in fact, i observed that on the simulator, the max speed i can do is always right where the max efficiency peak is on the graph.


So by having a goal of 115kmh, i add a kind of safe margin that have more chance to reach the 105-110km/h real goal (60-65mph) since the actual official world record is 58.6mph ( Lowell know that :wink

One more important thing is the air drag!!.. i did not calculated anything about that from now but my instinct say that if i go with a 20" rim, the bike will be 2" lower than using a 24".. so air drag can be ameliorated as well. and ameliorating air drag mean few km/h more for the top speed !

Than i tried many... eee.. MANY different matching between 5303, 5304, delta/Wye or not, 20" rim, 24" rim .. etc

What i know for sure is that with my actual setup(5305 100A 90V) I really reach 8650W max without any problem...

since riding at 50kmh require around 1500W on a MTB, riding at 100kmh would requier 4x that power that is 6000W continuous !.. .and 115km/h probably draw 8000W!

When i first imaginated a setup like that i thought using a 5303 on a 20" rim or a 5304 on a 24" rim... and on the simulator... BOTH results are VERY CLOSE !!.. the 5304 24" have a bit lower torque at 0rpm but a bit higher at high rpm!!
see pictures below.

So i would thing that since they are very close, their phase current would be probably the same or very close too right?.. lower rim diameter but higher rpm, less troque = higher rim diameter with low rpm higher torque... total would be same work.. same power?.. right?

so.. in this case, the 5303 on 20" have the 2" lower ebike setup advantage... and the the 5304 on 24" have the advantage of having 10% more torque at max speed...

so.. where is the trade off between little better acceleration and less air drag (5303 on 20" rim) and better top end torque but more air drag on the 5304...

The 5304 on a 20" rim instead on 24 is too risky, have not enough speed margin to ensure me for the 115km/h... and.. if it rach let say 100km/h.. this is too close to the actual world record.. and i would be dissapointed to just get like 57 or 58mph and not trully being above that 58.6km/h! with a 20" rim, with a 5303, the current will still be high to get the last km/h.. and less on the 5304.. ( for a same rim diameter)

I know that some say that the 5303 would draw more current for the same power.. but i dot think so because this one would be on a 20" rim diameter and the 5304 would be on a larger rim... so this is becoming equivalent right?

I know that at high speed.. maybe above 90km/h the torque is becoming more important because of the high air drag to fight with...

I think that both combinaison of the 5303 20"and 5304 24" would do the same results with the delta wye...

About magnetic saturation, like i said, i have often peaked at 8650W and ran on hill at max throttle needing 5500W continuous during 30sec with my actual 12fets crystalyte... so if i need let say 7500W during the last 10 sec of the 1/4 mile
that should not be a problem with a 18 mosfet controller...

NOTE: Since the simulator seems to not work for power above 5000W or 100A and HV, i've put the current limit to 50A instead of 100A.. so the top speed is the same in every simulations and the 50% power generated does niot affect the real top speed cause it does not take account of the wind drag that need more power...

Also, for the predicted results with the delta/wye system i just had 50% more volt since the real test showed me that the speed increase is more like 50% and not 73% like theorical calculations show...

but to recalculate the speed on the simulator, to make is still work at 140V, the curent need again to be reduced to keep under 5000W... Justin should ameliorate it for crazy people like some of us!!

Doc

 

[steveo]

Hey Doc,

If i have some time tommorw .. I will convert my 5304 to delta wye and add the air cooling!.. I will keep my 24" rim

Check my youtube .. i've posted some videos of my bike running 100 amps @ 79.2v very good quality.. i'm uploading as i post this.


Doc Please when you can search for a contactor for me !! .. I will actually go hunt for some contactors tommorw night at a garage door repair place.. they i was there about 1 week ago to fix my broken garage door openers .. and founf some nice size contactors that just Might work.

-steveo

 

[Doctorbass]

Hey Steveo.. i'll look for your video after i finish this reply :wink:

For the contactor.. here is the important parameters:

3PDT or 4PDT relay or contactor type

AC voltage rating of at least 100V

AC current rating of at least 30-40A

some will show DC contact current rating and often you will notice that the DC and AC rating are different.. normally a DC rating of 30V will easyly take 100V AC.. it's because in DC, the plasma arc generated by the release of the contacts is less important for AC than for DC. In AC, the voltage change of direction 60 time a sec.. so the arc just die every time the voltage cross zero on the sinewave... on DC, the voltage on the contact is ALWAYS present and the arc will sustain more time and let the contact to heat more and dammadge more...

so probably a 12VDC rated relay can take at least 75V in AC... and AC is type of current on the 3 phase wire!!

Doc

 

[Doctorbass]

Wow.. that's a nice video you did!.. it really show the awsome acceleration of an X5 at 0:45
http://www.youtube.com/watch?v=1XFTN0Gexfs

i've calculated on the simulator your exact setup.. and guess what.. it predict the exact same speed as you did!!

( note that i simulated it at 50A and not 105A cause it wont display anything above 5000W)

Doc

 

[ZapPat]

Just remember Doc that Justin's Simulator does not take into account any phase current limiting that may be happening in the controller (if you use an infinion).

I actually thought you where aiming more for an accelerating record than a max speed record. I guess the potential extra low speed torque provided by the 5304 vs 5303 working under phase current limiting conditions wouldn't be a necessity for just a max speed record. If you're drag racing with others though it might become an issue.

BTW Doc, do you know the resistances of the 5303/04 while cold?

 

[momo]

We need a transmission built into these hubs. At least 2 - 3 speed with a front shifter.

 

[steveo]

We need a transmission built into these hubs. At least 2 - 3 speed with a front shifter.

star/delta is basically a 2 speed!

-steveo

 

[Doctorbass]

Just remember Doc that Justin's Simulator does not take into account any phase current limiting that may be happening in the controller (if you use an infinion).

I actually thought you where aiming more for an accelerating record than a max speed record. I guess the potential extra low speed torque provided by the 5304 vs 5303 working under phase current limiting conditions wouldn't be a necessity for just a max speed record. If you're drag racing with others though it might become an issue.

BTW Doc, do you know the resistances of the 5303/04 while cold?

I agree about that phase current limit..... i'm still not sure i'll go with a infineon 18 mosfet controller or the crystalyte 18 mosfet...

About the resistance I only know the resistance phase to phase of my actual 5305. I measured it with the 4 wire method... so it is very accurate.

about the 5305:
The resistance between two phase wires: (tested at 10A DC with V measured directly on the winding wires connections (4 wires sensing measurement for better accuracy)

- measured voltage is 1.41V so R= 1.42V/10.0A= 0,142 ohms between two phase in serie

so the max current that motor should draw between two phases is: 7.04A/Volt in DC operation.
The voltage loss in the Anderson Powerpole Y-B-G connectorstested at 10A DC with V measured directly on the rear connections blade of both male and female of the powerpole connector (4 wires sensing measurement for better accuracy)

- measured V loss at 10.0A = 10.4mV and R= 1.004 mohm... very low!!!

The measured winding wire diameter: 0,0285" dia

= AWG 21 !! but there are 4 parallels in a 5305...

and that's 12.77mohms per ft

and 4 parallels AWG 21 are equal to one AWG 15 wire... = 3.19 mohms per ft

so we can conclude that the total winding lenght between two phases is
142mohm / 3.19 =44.5 ft and one phase = 22.2 ft wire long.


Steveo, can you measure that on your 5304 please?..

Doc