Increasing motor speed in 72V 10kW BLDC motor - help pls

[Praveen]

Hi recently I have bought 72V 10kW BLDC motor and HPC500 series controller.Everything is working fine from Golden motors.But the motor speed is nearly 4500rpm only while it supposed to run to max of 6000rpm . due to this my vehicle top speed is affected.Is there any possibility to increase the motor speed to reach till 6000rpm ?.... I have got usb programming kit also for the controller.i have changed the values in controller for motor to 7000rpm both fwd and rev.yet it doesnt run beyond 4500rpm.

Any ideas,suggestions pls !!!.??


Regards
 8)Praveen

[truly_bent]

The 6000 rpm motor speed in the specs is the "no load" speed. A good rule of thumb to determine "loaded" speed is to use a factor of 70%.

6000 x 0.7 = 4200.

Depending on the load, position of Venus relative to Mars, and all other factors, i'd say you're doing pretty well at 4500 rpm loaded.

The only way you'll increase your speed is to up the battery voltage, change the gearing (with loss of torque), or go on a severe diet.

In my case, the diet would help a lot.
Jeff

[Praveen]

Hi jeff
Thanks for the reply.
To clarify some specs.

1.)The speed which I measured using tachometer is at Motor "no load speed" only.It measured only 4500rpm to the max.

2.)The suggestion u did thatis to change gears is good.I tried it...it reaches max speed.but I cant start quickly(acceleration) in heavy traffics.So I cant compromise torque for speed.

[truly_bent]

My read of the HPC series user guide (http://www.goldenmotor.com/HPC%20Series%20Controller%20User%20Guide.pdf) shows pin 7 as accelerator input. I think it should read "speed setting", but that's semantics.

Anyway, if you could get a meter reading off this pin 7 (reference GND on pin 8 ) it would be useful. Presumably, +5V will give max speed. Check to see that you're getting something close to this. If you are, then i'd be checking parameter settings of the controller. I can't help you there because I don't have the software and I haven't seen a parameter listing.

If your readings are significantly below +5V, i'd start looking at the throttle.

Sorry can't be more help. You need Higher counselling
Jeff

[Praveen]

hi I checked the foot throttle voltage...its 5v.  .
Hi I will post the pictures of software  ...help me pls.

Attaching photos of controller software tabs.The following 3 tabs seems meaningful for changing motor speed .So I am posting these 3 tabs pictures.As u can see in controller tab.rpm is set to 7000 both forward and reverse.

Help Pls !!!!

[truly_bent]

I don't see anything out of the ordinary in there, except an unidentifiable number of pole pairs (2nd image top left).

Before I noticed that though, the idea of questioning the number of motor poles had occurred. I had a couple of pole count issues on my build as well. At one point I think I was running at half speed... if memory serves.

But, you really need more eyes on this thing. Might be a good time to yell for The Perfessor (Alan).

Jeff

P.S. If it makes you feel any better, I spent all of yesterday setting up several VFD's (Variable Frequency Drives) and soft starters for motors ranging from 10HP to 75HP at 480V 3ph. Got 'em all running, in spite of panel build wiring issues (Grrr...). I understand how frustrating these things can be.

[Bikemad]

It might be possible to wire the motor differently to give a higher speed. 
If my memory serves me right, the 10kW motors have six separate connections for the phase wires which should allow them to either be wired in Star (Wye or "Y") configuration for torque, or Delta configuration for speed.

I'm guessing it's most probably connected in Star configuration at the moment, reconfiguring it for Delta should make a big difference to its top speed.

You may need to email David (wyh@goldenmotor.com) for more information on configuring the phase wires.

Alan
 

[Praveen]

Hi as u said I have to look closer regarding the pole pairs and il post further.....meanwhile I have 6 separate wires coming from motor . 2 yellow , 2 blue , 2 Green wires . presently I have wired motor and controller as per the photo shown.

I don't know how do the motor configuration inside is....is this star or delta connection  ?
pls guide me ....

[Bikemad]

I'm even more confused now I've seen your photo as I was expecting the different colour pairs to be connected to either end of each phase winding, but I don't think it would run at all if they were separate ends of the windings and joined together as per your picture.

It would appear that the configuration of the windings is not user adjustable as I had first assumed. Perhaps it simply uses two parallel wires for each phase to help carry the extra current.

What voltage are you running your motor on and what is the maximum current that your pack can supply?

Alan
 

 

[truly_bent]

Glad you said that Allan. I was confused too.
If each winding had it's own color, then this termination would result in no electrical pathways.

I'm afraid to even hazard a guess.

Jeff

[Praveen]

hi thanks for the reply..


I am running my motor @ 72V system using Lead acid battery pack six nos(each battery has 120Ah).

Motor is running too in this connections,i have seen max amps 250A at one point drawn from battery packs.

regards
praveen

[truly_bent]

Okay then. I'll bite.

That implies that these leads are not the actual winding ends, but simple conduits. They look to be about 10 awg. At your amperages a single multi-strand 10 gauge wouldn't be enough.

If that's the case, and those leads are running directly into the motor, then the actual winding configuration would have to be inside the motor casing.

I'm really willing to be proven wrong here.
Jeff

[Praveen]

So is that the end ?.... . We cant do anything ?...i have to run only with 4500rpm ?

[Praveen]

how to find number of pole pairs ?.... ....any idea ?

[truly_bent]

Sorry. I didn't mean to imply that was an end.

If you're willing to crack open the motor casing, then you can (or should be able to) access and identify the 3 phase windings (6 leads). Having identified said windings, you should be able to determine whether it's connected Wye or Delta. I'll leave you that as homework, cause there must be a zillion Google Pics.

Let me point out however, that windings configured inside a motor casing would be rare. At least rare in my experience... In fact, i'd have to say I've never seen one done that way (unless my little grey cells are dying ). In my defence, i'd have to say that none of my industrial clients has asked for a review of a Chinese motor. I might have missed something here.

I don't know how experienced you are. I might dive in feet first to resolve a mystery like this, but i'd suggest you get a second opinion, such as Alan's, before going further.

If you don't have much experience and you're going to dive in anyway, please make sure the battery is disconnected first.

...I'm jus' sayin' is all. He might have kids.
Jeff