# Large BLDC or PMDC motors?



## Matej (Dec 4, 2015)

Hello,

Are there any large brushless DC or permanent magnet DC motors that can readily be sourced, either new or used?

BLDC motors can of course be obtained from EV's such as the Leaf motor which is affordable and easy to find, but their voltage and rpm's are too high and the current too low. They are also very difficult to custom adapt to anything because they use proprietary shafts that slip into the gearbox and their end shaft bearing is weak, if they even have one.

I am looking for something a bit more industrial and universal, with a max rpm of 6000-8000, 120-200V, and high current. Pretty much a BLDC or PMDC equivalent of a Warp9 or Warp11 motor.

Does anyone make such motors?
Can they be found in any equipment, similar to how large series motors can be obtained from old forklifts?
Do such motors even exist?

Thank you.


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## brian_ (Feb 7, 2017)

I don't know what you would salvage this sort of motor from cheaply, but as a new product, NetGain has contracted with a motor manufacturer (SME) to provide a low-voltage (up to 130 V) AC PM motor and sells it (as a package with a controller) as the "HyPer9".

It is intended as a AC PM replacement for NetGain's Warp motors.

While I think that the typical "industrial" style of shaft of the HyPer9 is poorly suited to automotive applications (no auto engine has a plain shaft with a keyway), it is what everyone gets with their "forklift" motors and seems to be what you're looking for.

Previous threads in this forum about the HyPer9:

AC Motor Offered by NetGain Motors, Inc.
anyone heard of this hyper9 ?
NetGain AC Motor


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## brian_ (Feb 7, 2017)

Matej said:


> BLDC motors can of course be obtained from EV's such as the Leaf motor which is affordable and easy to find, but ...
> They are also very difficult to custom adapt to anything because they use proprietary shafts that slip into the gearbox and their end shaft bearing is weak, if they even have one.


One way to address the shaft interface issue is to use the transaxle on which the motor was originally installed, as well. Of course this doesn't fit where desired in many conversions, but where it will fit this is a good solution.


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## Nuts&Volts (Dec 20, 2011)

Find a used fisker karma motor. I’ve seen some on eBay. 6000RPM max with high torque. 


Sent from my iPhone using Tapatalk


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## brian_ (Feb 7, 2017)

Nuts&Volts said:


> Find a used fisker karma motor. I’ve seen some on eBay. 6000RPM max with high torque.


That's an interesting idea. It is large, and a PM AC motor. It is much larger in diameter than the Warp motors, but it is also much shorter. I've never seen any information about the output shaft configuration, but it seems to be designed for a single stage of reduction to the Karma's rear wheels (a right-angle final drive).

The design voltage for this motor won't be any lower than that of a Leaf.

Here's a recent discussion:
Fisker Karma motor ?

Then there are these guys who use one or two Karma motors for a heavy truck:
http://www.transpowerusa.com/
It appears that the motor output is a female spline. If you're astoundingly lucky, the spline might match the input shaft of some manual transmission that you would want to use with it.


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## Matej (Dec 4, 2015)

brian_ said:


> NetGain has contracted with a motor manufacturer (SME) to provide a low-voltage (up to 130 V) AC PM motor and sells it (as a package with a controller) as the "HyPer9".


For some reason I thought that the HyPer9 was an induction AC motor. You are correct, their website states that it is a 'Synchronous Reluctance Internal Permanent Magnet' motor, although I am not really sure what that means.

Does such a motor behave similarly to a BLDC motor?

I am looking for something that could potentially also be easily used as a generator, hence my interest in BLDC and PMDC motors.


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## brian_ (Feb 7, 2017)

Matej said:


> For some reason I thought that the HyPer9 was an induction AC motor. You are correct, their website states that it is a 'Synchronous Reluctance Internal Permanent Magnet' motor, although I am not really sure what that means.


It's really just a permanent magnet synchronous AC motor, like every current production EV other than the Tesla Model S and Model X. The magnets are internal to the rotor (rather than at the surface), which is also current normal practice. They leave holes in the rotor laminations to guide the magnetic flux, which makes paths of different reluctance... which other PM AC motors do as well. As a PM motor it is synchronous: the rotor turns in synch with the applied power - there is no slippage.



Matej said:


> Does such a motor behave similarly to a BLDC motor?
> 
> I am looking for something that could potentially also be easily used as a generator, hence my interest in BLDC and PMDC motors.


It depends on what you mean by "BLDC". If you mean a motor which is designed specifically to work with on-off switched power, then not really. If you mean an AC PM motor - driven by 3-phase sinusoidal power to the stator and with a permanent magnet rotor - then yes, that's what it is.

A normal permanent magnet DC motor uses a wound rotor powered through brushes and a commutator, and a permanent magnet stator to provide the fixed field. Definitely not like that.

AC PM motors generate just fine (that's the regenerative braking of all production EVs), and inverters/controllers for them normally support that operation.

The HyPer9 is like any PM AC motor, with constant current-limited torque to a transition point, then constant power (current and torque dropping off) for a while, then power dropping off because the supply voltage isn't enough. Production EV motors don't usually see much high-speed power drop-off because they work with more supply voltage. There are torque and power (and current) curves published for the HyPer9.


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## Matej (Dec 4, 2015)

So the HyPer9 could simply be rectified with a three-phase bridge rectifier into DC power if it was used as a generator?

This is embarrassing but apparently I have been calling motors by the wrong name, as I always just called the Leaf motor and others like it BLDC motors.


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## brian_ (Feb 7, 2017)

Matej said:


> This is embarrassing but apparently I have been calling motors by the wrong name, as I always just called the Leaf motor and others like it BLDC motors.


That's actually very common... which is why I wanted to clarify the intent.


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## brian_ (Feb 7, 2017)

Matej said:


> So the HyPer9 could simply be rectified with a three-phase bridge rectifier into DC power if it was used as a generator?


Yes, The problem is that with a permanent magnet field, there would be no control of the generation rate - it would be full-on, with available voltage dependent on speed and current depending on the attached load (the battery). I assume that you would want to go through some sort of charge controller, and an inverter intended for EV use with PM AC motors would normally provide that function.


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## John Metric (Feb 26, 2009)

I am trying to build and supply that. It is basically a high current BLDC motor that directly couples to Lenco Racing Transmission, or any other transmission you would want. We rolled it out at the PRI in Indy, a year ago.
I have been trying to tame it, but it is breaking my 2400HP transmissions.
We are adding a current ramp feature into the controller because it just comes on too strong to quickly.


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## Uday (Mar 9, 2021)

Matej said:


> Hello,
> 
> Are there any large brushless DC or permanent magnet DC motors that can readily be sourced, either new or used?
> 
> ...


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## Uday (Mar 9, 2021)

Matej said:


> Hello,
> 
> Are there any large brushless DC or permanent magnet DC motors that can readily be sourced, either new or used?
> 
> ...



Visit for a custom solution for BLDC and PMDC motors. - Brushless Servo Motors | MoveMatic | Aurangabad


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## saxere7 (Nov 19, 2021)

Matej said:


> Hello,
> 
> Are there any large brushless DC or permanent magnet DC motors that can readily be sourced, either new or used?
> 
> ...


Hi all 
I'm in need of some help looking for a new brushless motor for my rc car
my car is a gv/bel cage and the old motor was a 2370 kv was running on 4s was hoping for something similar if possible 
I know there probably lots out there but do any of you recommend a good one 

many thanks


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## saxere7 (Nov 19, 2021)

Matej said:


> Hello,
> 
> Are there any large brushless DC or permanent magnet DC motors that can readily be sourced, either new or used?
> 
> ...


Hi all
I'm in need of some help looking for a new brushless motor for my rc car
my car is a gv/bel cage and the old motor was a 2370 kv was running on 4s was hoping for something similar if possible
I know there probably lots out there but do any of you recommend a good one

many thanks


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## John Metric (Feb 26, 2009)

saxere7 said:


> Hi all
> I'm in need of some help looking for a new brushless motor for my rc car
> my car is a gv/bel cage and the old motor was a 2370 kv was running on 4s was hoping for something similar if possible
> I know there probably lots out there but do any of you recommend a good one
> ...


Sorry ,we don't do any RC car motors. We can send you a battery that will blow your controller up. 4S, 5S, 6S, 7S etc....


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