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

[Morgen 3Eman]

Hi Folks,

My experience about motor windings is like yours, with the ends of the windings available external to the motor, often in a little box nicknamed the "peckerhead" because of its distinctive shape.

However, it looks to me like the winding ends are available :  the yellow wires connect to the ends of two windings, the greens to the other ends or other windings, and the same for the blue pair.  So I think you have the ability to change the configuration from the delta it looks like to me.   You can Ohm them out by separating the colored pairs. 

I need to take a look at the photos again......

TTFN,
Dennis

[Morgen 3Eman]

Yea,  my next guess is that if you disconnect all the phase wires from each other, the yellows(or greens, blues) will be an open circuit to each other, and a low resistance to one of the other colors. 

Test it and find out, and then you can configure it as a star or delta as you wish. 

And I have no idea if it will affect your rpm......Are you using direct drive so you can't change drive ratios?

TTFN,
Dennis

[Praveen]

Thanks for the reply............

hi I do have a little box  "peckerhead" at the end of each terminals in my 72V motor ....i will post motor photo asap clearly...

il check resistance across terminals and come back to you..!!!

Regards
Praveen

[truly_bent]

By "peckerhead", I presume you mean Marr connectors?

[Morgen 3Eman]

Look closely and use your imagination, while you think "peckerhead".

TTFN,
Dennis

[Praveen]

Hi I m showing my motor photo with marr connectors and pecker head box. I have labelled picture.correct me in case if I am wrong.


Actually I have 2nos yellow , 2 nos green , 2 nos blue cables running out from that "box" along with 2 black wires has connectors for hall sensors.

Do u think if I open that box I can change wiring configuration (delta/star) and so I can increase my motor speed ?

Regards
Praveen

[Morgen 3Eman]

Hi Praveen,

Ignore my comment about the wiring in the peckerhead.  It was only for industrial motors I have worked with. Also, I have to tell you that I have no idea if changing the configuration of your windings will effect your max speed.   And no idea about your software's ability.   Apparently Jeff has considerable experience in those areas.   I do , however, have some experience in a lot of other things. 

What I was talking about was based on your photo of your controller.  It seems to show two yellow, two green and two blue wires attached to their respective terminal studs, for a total of 6 wires.  6 wires are required for 3 phase windings.    So it looks to me like the motor is currently delta connected.  By removing the 6 wires from the controller terminals  you can Ohm them out and confirm they are indeed the ends of the phase windings. 

And since I'm typing,  I'll waste a few more moments of your time.  One thing I have learned in over 50 years of hot rodding various things is  that you can have speed, or torque, or money.     But not all three.  You get to choose.....

TTFN,
Dennis

[truly_bent]

For the sake of argument, let's assume that each winding has it's own color. The earlier picture of the controller would put each winding in a physical loop (yellow-yellow, green-green and blue-blue) to each output terminal. Clearly, that cannot be the case since no electrical pathways would exist. (I'm just repeating myself here).

If the motor windings were connected directly to the controller output terminals in a Delta configuration, one would expect to see yellow-green, green-blue, and blue-yellow on the terminals. I'd be surprised to find the motor all ready configured as Delta - especially running that slowly against spec.

I don't think this is going to get resolved until Praveen cracks open the motor, with Alan's blessing I hope. Of course, Alan might be off playing Shuffle Board or a Bingo game. These cruises can get pretty wild.

Jeff

[truly_bent]

Before going and cracking open the motor casing, i'd try to find the motor pole count and see if it agrees with the controller parameter setting. Might be as simple as that.
J

[Morgen 3Eman]

Hi Jeff,

Please forgive me, but I'm afraid I must disagree with your assumption of each winding having its own color.  Like you said, there would be no current path.  Since the motor does spin, there must be a current path.  So the colors must be meant to convey something else. 

So here is what I am trying to communicate:  Customers are often assumed to be ignorant by manufacturers.  Thus, the wires are color coded to hook them up to the manufacturers controller, not to indicate which wire actually connects to a particular winding.  There is no need for L1,L2,L3, etc markings, as is common with industrial motors.  Just hook the two yellow wires to the yellow terminal, the two green, etc. 

A simple test with an Ohmmeter is needed to confirm the point, but since the motor spins, I think the point is moot.   No need to open the motor. 

And I'm hoping Alan is doing something more exciting than shuffle board.   Water skiing behind the boat, maybe? 

TTFN,
Dennis

[truly_bent]

Yes, it's possible that the manufacturer color-coded each each winding end differently. I'm doubting that though, since doing so would likely add additional handling costs to the build process. But, maybe you're right.

The windings in your scenario would have to be configured Delta, and that's another point that sticks in my craw. I wouldn't expect the manufacturer to choose speed over torque. I'm betting that it'll be configured Wye.

As it so happens, I was wrong once before. Happened back in '89 (... a long and boring story follows).

Jeff

[Bikemad]

And I'm hoping Alan is doing something more exciting than shuffle board.   Water skiing behind the boat, maybe?

Dennis, I don't need to dangle myself off the back of the boat as it has its own "Flowrider" on the top deck:



Anyway, it looks far too risky for me, I'm hoping to be brown all over when I return to the UK - not black and blue!

Alan
 

[Morgen 3Eman]

Hi Alan!

That looks like a great deal of fun.

I'd like to watch with a bevie in hand, tho.

Enjoy your holiday.  We'll be fine.

TTFN,
Dennis