HPM5000B more than 72V ?

[Andreas Keim]

Hello,

my name is Andreas. I´m planing an electric motocross/enduro bike. To get more power I want to increase the voltage up to ~ 84V (or more?). Is this possible with the 72V winding version? How many magnetic poles has this motor? Do you have a controller for this? Will this motor work well with Kelly controllers, for example? http://www.newKellycontroller.com/product_info.php?products_id=51

My minds to this: Voltage doesn´t kill an electric motor, if you are in specs with current and rpm. Of course you have more power and with nearly same efficiency you will get more loses and thereby more heat.

Thank you in advance for a answer!

Regards,
Andreas

[Leslie]

There has been no indication yet of any difference to the 72v version and any other version of this motor.

I run a HBS36 at 60v and so far so good.

Upon my work with inductors I've found you can use the motor as a type of buck converter by limiting the PWM width to the motor.  

I have found the higher voltages you push into the motors windings, if the motor winding and core size are not enough for these higher voltages more heat is generated by the lower resistance windings and in a moment the voltage saturates the core with magnetic intensity with little or no gains to MF.  More winds can convert the flux field intenisty into magnetic density. either or both can saturate the core leaving no room for either to give an more gains.  The core can only present so much reaction to the current and voltage.

  Observation over a coil and switcher with different taps along its turns yield identical voltage at each tap and more current was available the shorter the tap was from source.  To turn the voltage into magnetic intensity (throw or K) one must make sure some rules are adhered to for it to remain efficient at top speed.

The stator in the motor is based on transformer electro-mechanics with a iron core. And its said around an iron core 6 enamel wire turns around a former for every 1.2v is a good guide to get the most efficiency from any winding.  The thickness of the windings decreases the resistance and increases the current available for magnetic density (torque).

When you stray too far from the basic rules you lose efficiency and the top speed gains are not easy to attain when you overvolt too far.

With my 60v overvolt am lucky to get an extra 20kph for the extra 24v, but any extra over 10kph from the hubs normal top speed takes a good chunk of capacity from my pack.

My HBS36 has 34 slots between two phases that make the circuit when operational.  If I run 50v PWM pulses into 34 slots divide 50V into 1.2v the the product of that into 34 slots = 1.22v per slot times by 6 turns = 7 turns per former.

With the same equation for a 75v supply I would need 10 or even 11 turns per former to convert the voltage into MF.

At 75v with 34 slots and seven turns on each slot,  each will exceed the rule above by .6v and over 20v for 34 slots.

Without knowing resistances you can take a guess that a 24v overvolt will probably cost you an extra 5 amps and bring the efficiency of the motor down to an average of 25%.  

All ball park figures here.

At best the motor runs at 85% efficiency now running at 60% efficiency, 40% of 5 amps at 20v can reach 60 watts of power wasted.  This is what I approximate my losses are at full throttle with the 36v hub at 60v.

If you have the power to waste for an overvolt like this then it would be fine.  But I feel overvolting has only so much to be gained, if done right and limit the duty cycle of the PWM a bit more distance and a bit more speed one travels is the target of such a pursuit.

It will work and probably well too, but it's no magic fix and you may find yourself cutting throttle voltage a little to make it worth while
 

[Andreas Keim]

Thank you!

What is the rpm/V of the 72V version? Is there a performance curve available? I think this one http://www.goldenmotor.com/hubmotors/48V5KW-09052602-3800RPM%20Performance%20Curve.jpg is from the 48V Version. Knows somebody the number of poles? The Kellycontroller can handle up to 40.000 field rpm (in available speed version 70.000)

regards,
Andreas

[Bikemad]

Andreas,

As far as the poles are concerned, I'm guessing from these pictures that there are 24 slots on the windings and 16 poles on the magnets. (8 magnets using both poles, as I think they are too wide for a single pole).

I don't know whether the figures used for the field rpm are for a single phase or for all three, so it could end up with either 5,000rpm at the spindle or just 1,667rpm.

I'll let you decide for yourself, because I don't know.

Alan
 

[Andreas Keim]

Hi Alan,

thank you for the pictures. It seems for me that there are 8 magnets --> 4 pole couples. That means 6000rpm x 4 pole couples = 24000 field rpm. Phases doesn´t have an influence of the field rpm.

When I know the rpm/V I can start to calculate the gear reduction. A data sheet especially for the 72V version would be great.

best regards
Andreas

[Bikemad]

I was thinking 8 magnets --> 8 pole couples.
(N and S on the stator side of each magnet as per picture below)



Surly that would mean 5000rpm x 8 pole couples = 40000 field rpm?

Alan
 

[Andreas Keim]

Are you sure about N and S in one magnet? It could be possible and your theorie makes sense. I think the field rpm are not the problem, I will order the 70000 rpm speed version of the controller. Of course with higher field rpm you will get more eddy current loses in the motor, caused by the faster reversion of magnetic polarity in the stator. But this is too much theoretical.

[Bikemad]

Are you sure about N and S in one magnet?

No, I'm not sure, but having a single magnetic pole spanning three separate coils looks wrong to me.

Alan
 

[Andreas Keim]

Ok. I´m not exactly sure if it´s wrong. Both variantes (24slot-8poles and 24slot-4poles) should run. Only same numbers of slot and poles (24-24) can not run. But this discussion is too much in detail, Goldenmotors are running...I hope
Is the Goldenmotor-staff reading here, or should I sent an email with my questions ( rpm/V and datasheet)?

[Bikemad]

Is the Goldenmotor-staff reading here, or should I sent an email with my questions ( rpm/V and datasheet)?

You could try sending an email to Tom (zhourenli@goldenmotor.com), but you may not get a reply.
Perhaps it's just me he doesn't reply to.  

EDIT
I've been looking at information on this motor, and as far as I can tell it is the same motor which is just run on different voltages.

Perhaps someone from GM will correct me if I'm wrong.

From the 48V performance chart, I estimate around 78rpm/volt (3750rpm/48V), this should give an unloaded maximum speed of 6552rpm@84V.
It could even reach 7500rpm with a fully charged SLA battery pack (13.8Vx7=96.6V).

Alan
 

[Andreas Keim]

That sounds good. I think you are right with only one version of the motor. Otherwise with different windings the current load can not be the same. More windings --> less current load possible. There are no different informations on the website, so I think as you that there is only one version.
With the datasheet I have calculated in excel to get load rpm´s on higher currents. Rpm/V over the current load is nearly a linear curve. With this infos I can work! Thank you a lot

[Leslie]

For thos wishing to get an idea of how windings work here is a site called powercroco.

Although it is in german it translate to something cohesive.

http://translate.googleusercontent.com/translate_c?hl=en&sl=de&u=http://www.powercroco.de/navigation.html&prev=/search%3Fq%3Dpowercroco%26hl%3Den&rurl=translate.google.com.au&usg=ALkJrhgvszfFgLYNG5C-bWHhiD0-U-SywQ

The link I supply is of the site map as the front page is a little buggy due to the translation.

This next link is to the slot pole calculator.

http://translate.googleusercontent.com/translate_c?hl=en&sl=de&u=http://www.powercroco.de/Kombinationstabelle.html&prev=/search%3Fq%3Dpowercroco%26hl%3Den&rurl=translate.google.com.au&usg=ALkJrhiMI_BD8Y9Nyh1AqiUAQQKdOYv8bw

This certainly makes life for the newbies like me a lot easier.

Enjoy.

Edit:



I don't know if you can make out how this motor is wound like this.

[thehtcguru]

Any updates on this?

[Andreas Keim]

Hello,
the motor arrived yesterday, unfortunately it took 3 month from the order to the arrival, because the motor was not in stock and at last the tax office had the motor some weeks. Today I had connected the motor to the Kellycontroller and it´s running good. I glued a temperature sensor on the motor winding, to protect overheating. In the next weeks I´ll have not so much time for this project, but then I will start preparing the bike.
regards,
Andreas

[Sundsvall]

Please, keep us informed on this project. Looking forward to the updates and hopefully some additional pictures.

Peter