# Nikko Forklift motor... how to control it?



## RobSmith (Aug 13, 2010)

Hi All,
I have recently bought this motor:

















I am struggling to find any technical information about it regarding its speed, currents etc.
It has four terminals LA, LB are connected to the armature brushes and LE and LF are connected to the field windings.
The field windings have a very low resistance and a look on the web points to that being most likely a motor to connect up in series.

I am wanting to drive a lathe with this so with the lathe in high gear ratios and the chuck spinning fast there is a fair load on the motor. In low ratios where the chuck may only be doing 50 rpm the motor is under so little load it could just rev itself to pieces.
I am looking for an electrically fairly efficient way of doing this.
I will be running this from a 48v 450ah battery pack as part of our off-grid setup. The simplest speed control may be just an enormous resistor but this would convert a fair bit of power to heat which is unacceptable. It needs to be fairly efficient when we are running it off-grid.

Any ideas or help would be greatly appreciated.

Rob


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## Rational (Nov 26, 2011)

RobSmith said:


> Hi All,
> I have recently bought this motor:
> 
> 
> ...


I get a FL motor current of at least 2700w/48v = 56A.
If you measure the resistance at several rotor positions [don't move the rotor while the meter is connected] and the inductance [you'll need an AC source, a VOM and almost any resistor to measure this] a suitable speed control can be spec'd. I think.


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## Woodsmith (Jun 5, 2008)

I have a Curtis 1214, 36-48V controller on my Tractor. That would make the motor run.

However, as a speed controller it would allow the speed to vary with load so as you apply a tool the speed will slow down and off load it could spin to death.

You would be better off with a controller that controls the speed regardless of load and holds the RPM steady as you work. Torque controller*?
That might also mean that something other then a series motor might be a better starting point, a sep-ex, shunt or pm might work better.

Major would have better advice then I would at midnight.

*Now who was telling me about these being a problem on Electric motorbikes? Jozzer, I think.


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## RobSmith (Aug 13, 2010)

Woodsmith said:


> I have a Curtis 1214, 36-48V controller on my Tractor. That would make the motor run.
> 
> However, as a speed controller it would allow the speed to vary with load so as you apply a tool the speed will slow down and off load it could spin to death.
> 
> ...


Thanks for that. Hopefully Major will advise me.
I am not sure it is a series motor or not. The field windings have a very low resistance and with my lack of knowledge used Wikipedia and that points to a low field resistance being designed as a motor for series connection. If it was designed as a series motor why did they put four separate terminals on it. Could it be a Sep-Ex motor? I don't realy know hence asking 
Rob


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## major (Apr 4, 2008)

RobSmith said:


> Thanks for that. Hopefully Major will advise me.
> I am not sure it is a series motor or not. The field windings have a very low resistance and with my lack of knowledge used Wikipedia and that points to a low field resistance being designed as a motor for series connection. If it was designed as a series motor why did they put four separate terminals on it. Could it be a Sep-Ex motor? I don't realy know hence asking
> Rob


Hi Rob,

Yep, looks like a series wound motor to me. I think I've seen that model before on this forum. It has 4 terminals because it is reversible as it was used for forklift traction drive. Although it would have the guts to turn a lathe, it is not a good choice due to control difficulty. A good PWM controller with a speed feedback loop could be fashioned to work, but is unlikely to be found in a plug and play product.

If it was a shunt or separately excited motor it would be better suited.

And Woodsmith,

They commonly call them speed controllers, but when series (or other type) motor controllers are used for propulsion motor control in EVs, they function as torque controllers. If a guy was having problems with one on his motorbike, it probably was in speed control mode. With some types (like AC) of controllers, you actually have a choice of speed or torque control modes. Choose torque. With the PWM series and PM controllers, it is pretty fuzzy as to torque and speed control because it is a one to one function with a single controllable attribute (voltage). This is related by your typical speed torque motor performance curve which is voltage dependent.

Rob,

Put your nice series motor in an EV and get a shunt (or PM) motor for that machine 

major


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## Woodsmith (Jun 5, 2008)

major said:


> Hi Rob,
> And Woodsmith,
> 
> They commonly call them speed controllers, but when series (or other type) motor controllers are used for propulsion motor control in EVs, they function as torque controllers. If a guy was having problems with one on his motorbike, it probably was in speed control mode.


Cheers major, I thought I might have got that backwards.

My brain is still not quite right sometimes, seeing both a psycotherapist and a psycologist now to de bug the old grey matter.


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## Rational (Nov 26, 2011)

It'd be good if you can find desirable speed/torque curves for lathe motors.


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## RobSmith (Aug 13, 2010)

major said:


> Hi Rob,
> 
> Yep, looks like a series wound motor to me. I think I've seen that model before on this forum. It has 4 terminals because it is reversible as it was used for forklift traction drive. Although it would have the guts to turn a lathe, it is not a good choice due to control difficulty. A good PWM controller with a speed feedback loop could be fashioned to work, but is unlikely to be found in a plug and play product.
> 
> ...


Thanks for the reply. That is great. A couple of questions...

Is there a correct connection (ie which is +ve / -ve) on the field or armature windings? and which, field or armature, should be switched over to provide reverse direction? I can imagine there being some angular relationship between the armature segments and the field coils that make it have a 'correct way to wire it'

What sort of speeds do these motors normally run at?

What is the availability of a 48v PM motor of this sort of size?

... and how much might one cost?

... and can you improve the weather so I can get some work done outside? 

Rob


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## RobSmith (Aug 13, 2010)

I was thinking today.... not something I normally do 
I was thinking I could use this motor and make up a 'rev limiter' to cut the power between controller and motor when the motor got to a set speed. I may need some capacitors in there or something to have a short time delay so that the 'rev limiter' does not sit growling away to itself rapidly switching on and off.
I am not sure if the controller would like the power cut between controller and motor like that?
Would one of those Curtis golf cart contollers work with this motor?
Idealy I want 48v battery pack one side, motor the other side and a potentiometer to control the speed.

Rob


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## major (Apr 4, 2008)

RobSmith said:


> What sort of speeds do these motors normally run at?


Rob,

Machine tool conversions are a bit off-topic. At nameplate load, maybe around 2000 RPM. You can find answers to a lot of your questions by looking around this forum. Searching for nikko I found this: http://www.diyelectriccar.com/forums/showthread.php?t=60139&highlight=nikko 

major


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## RobSmith (Aug 13, 2010)

major said:


> Rob,
> 
> Machine tool conversions are a bit off-topic. At nameplate load, maybe around 2000 RPM. You can find answers to a lot of your questions by looking around this forum. Searching for nikko I found this: http://www.diyelectriccar.com/forums/showthread.php?t=60139&highlight=nikko
> 
> major


Thanks for your reply. 2000rpm is a useful sort of speed for what I want.

I found that thread before and it is possibly exactly the same motor. He is in much the same situation as me....not being able to find much about it.

I will have a look around the controller section and see if I can get some clues in there too.

Rob


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## RobSmith (Aug 13, 2010)

That sounds like a fairly reasonable observation.
Thanks
Rob


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