Replacing magnets for more power

[waingroo]

Hi,

I would like to know if changing neodymium magnets with powerfull ones (e.g. N52) at the same size will increase the torque of motor at the same watts?

In my case, is about an axial brusshed type of hub (Heinzmann) with round axial polarized magnets.

Also, if i do some modification, i can replace with thicker magnets. This mean to make thin about 1mm the plates where magnets are placed.

thanks

 

[skoleskibe]

I Think not.
Anyhow i do have several heinzman motors, the old 24v 400w type. If you use a controller that isn't current limited, you can easily push 40-50amps, at which current the frontwheel will loose traction on anything other than asphalt.

 

[Sunder]

Hi,
I would like to know if changing neodymium magnets with powerfull ones (e.g. N52) at the same size will increase the torque of motor at the same watts?

In theory it will - but at a cost of KV.

In reality, there are a lot of other things that could affect that answer. For example, if you were already close to stator saturation, then you'll just generate more heat instead of torque. I'm not an electrical engineer though, and others may be able to explain better than I can.

Short answer is that there are probably easier ways you can get more power out of your motor.

 

[dogman dan]

True, just get a stronger controller. Make sure you use the heat cutoff switch in line with the ignition wire of the controller, and give it 36v 30 amps. It will wail then, but still stop before it overheats if you are climbing too steep hills.

 

[waingroo]

I Think not.
Anyhow i do have several heinzman motors, the old 24v 400w type. If you use a controller that isn't current limited, you can easily push 40-50amps, at which current the frontwheel will loose traction on anything other than asphalt.

Thanks ll of you for answe, but there is one more think:

Years ago, on this forum, one guy has sold a heinzmann of 80Nm, most probably from EV global bike.

Mines are 34Nm 250W 36V... as a fan of this motor I collect them LOL

I'm just think if the windings is the same to all of them and the stickers applied to the case depend about the controllers with they are delivered !?

I remember that someone tell on a page about heinzmann that these motors can support up to 1000W. If is like that, then IMO all motors are the same and is just the controller the one who limmit torque.

Here is another guy who ask almost the same think and bring answer from D8veh http://www.pedelecs.co.uk/forum/threads/heinzmann-motor-understanding-specs.13841/

PS. one more question. The plate where the four brushes are placed can support another four. What about this?

 

[Drunkskunk]

The controller is a separate issue. Allowing more power into the motor will make it more powerful, up to the point were it overheats or burns up the brushes.

The magnet strength is something carefully engineered. In very general terms, stronger magnets give more torque, but make the motor less efficient and kill it's top speed. In less general terms, you could reach a situation where the motor reaches it's satiation point at lower power than your controller is feeding it, causing less torque to be produced after modification, and causing significant heating.
In other words, you might fail at making a more powerful motor, but succeed at making an effective induction cook top.

I believe the other set of brush holders are set at a slightly different advance angle. One set gave more speed, while the other set ran a little more efficient. I forget which was which.

 

[waingroo]

The controller is a separate issue. Allowing more power into the motor will make it more powerful, up to the point were it overheats or burns up the brushes.

I believe the other set of brush holders are set at a slightly different advance angle. One set gave more speed, while the other set ran a little more efficient. I forget which was which.

Thanks for explanation! Here i add a photo with the brush support. It is not made by me, but can be well observed.

 

[John in CR]

Hi,

I would like to know if changing neodymium magnets with powerfull ones (e.g. N52) at the same size will increase the torque of motor at the same watts?

In my case, is about an axial brusshed type of hub (Heinzmann) with round axial polarized magnets.

Also, if i do some modification, i can replace with thicker magnets. This mean to make thin about 1mm the plates where magnets are placed.

thanks

No. Heinzmann's are engineered well enough that they would have simply done it themselves.

 

[dogman dan]

I tend to agree with that. Those Germans would have dialed it in good. I'm not sure if there are any real differences between the 250w heinzmann, and the 400w one used on the EVG. Mine were old EVG motors.

But in any case, the 3x rule still applies, so I would not hesitate much to run 36v 20 amps controller, 750w peak power through the 250w.

 

[waingroo]

I tend to agree with that. Those Germans would have dialed it in good. I'm not sure if there are any real differences between the 250w heinzmann, and the 400w one used on the EVG. Mine were old EVG motors.

But in any case, the 3x rule still applies, so I would not hesitate much to run 36v 20 amps controller, 750w peak power through the 250w.

Do you think i can replace my controller with a 500W one withowt any problem?

One think i haven't told about mines. What i have are called Egston 32V 250W.... 100% Heinzmann, same gears, same case, but KTM ebikes wanted to be rebranded. The difference is that the egston have not thermostat and only two wires are come out instead four. The egston controller is 31.2V.

 

[skoleskibe]

I've run 36v 40A through my 24V 400W heinzmann, if done properly, ie few seconds at a time, the heinzmann is a monster motor. I've bought my motors through german eBay.
It's paramount to remember not to use it as a 750 or 1000w motor all the time. Used with comon sense it's a marvelous motor. I've used with a watt meter to monitor my comon sense

 

[waingroo]

I've run 36v 40A through my 24V 400W heinzmann, if done properly, ie few seconds at a time, the heinzmann is a monster motor. I've bought my motors through german eBay.
It's paramount to remember not to use it as a 750 or 1000w motor all the time. Used with comon sense it's a marvelous motor. I've used with a watt meter to monitor my comon sense

Yes, I live in a hilly area and I only need high torque for a few seconds. I'm a hunter of these motors because of their realiability. I even forget about any other motor. Heinzmann is just simple hight quality motor IMO without too much electronics and is just I need.

Perhaps yours (400W 24V) comes from Zokes ebike. Mines only come from KTM front wheel. One guy promise to sell me one from an Estelle... also front wheel.

If i don't find a rear one, i-ll try to convert a front one adding gears support somehow...

What controller do you recommend? I would like something reliable and not interested about pedall assist. Just simple throttle. My battery is a Li-Ion Tranzx 36V 9AH. Trekking bike Pegasus.

 

[skoleskibe]

Well, I'll not recommend any specific controller, but the one i'm using is a Porter from 4qd in England. It uses a magura throttle. It's rated at 30A afaik. I've measured up to 51A from a 10000 mAh 8s multistar battery.
I do have an empty housing for a rearwheel, however you'll need a longer axle if you want to use it with more than 1 gear at the rear.

 

[waingroo]

Well, I'll not recommend any specific controller, but the one i'm using is a Porter from 4qd in England. It uses a magura throttle. It's rated at 30A afaik. I've measured up to 51A from a 10000 mAh 8s multistar battery.
I do have an empty housing for a rearwheel, however you'll need a longer axle if you want to use it with more than 1 gear at the rear.

Thanks for advice... I have to wait until i find a Zokes or Ev Global for sale to get a rear case. How much yours in case you sell it. I think a single speed is enough when have a heinzmann.

This mean that even if i get one rear motor from an Ev Global, i must need a longer axle? I never seen a rear one, just in photos. Just measured and there are like 13cm between rear dropouts (fitted a nexus inter7).

watching this photo i can deduce almost same distance

 

[dogman dan]

I would not hesitate a moment to run 500-750w through it, up to 36v 20 amps. To monitor temperature, you can add an internal, or even external digital thermometer.

I ran the thermometer and the cut off on my heinzmann, because I hated being surprised by the cut off. I had 36v 30 amps, so I'd overheat a bit faster. The reason I'd overheat, was that I was trail riding. Cruising on the street should be little problem, unless you have really long steep hills to climb, hills miles long.

Just grab any brushed controller and throttle off ebay. Usually scooter stuff, and cheap.

 

[waingroo]

I would not hesitate a moment to run 500-750w through it, up to 36v 20 amps. To monitor temperature, you can add an internal, or even external digital thermometer.

I ran the thermometer and the cut off on my heinzmann, because I hated being surprised by the cut off. I had 36v 30 amps, so I'd overheat a bit faster. The reason I'd overheat, was that I was trail riding. Cruising on the street should be little problem, unless you have really long steep hills to climb, hills miles long.

Just grab any brushed controller and throttle off ebay. Usually scooter stuff, and cheap.

I know there are two type of Heinzmann like S1 continuous and S2 duty. From what I understood, S1 can run even overheat. The old type (steel cover sheet) are S1... most of them. Mines are S2.

Adding an external thermometer is a great idea! thanks for this clue
Most of hills in my city are short, like 200 metters. I have to add a bike inclinometer , but i think most of them are less than 12%.