# ADC Maximum Voltage?



## favguy (May 2, 2008)

Hi,

At 180 to 190 you are already over maximum safe voltage for this motor, if you go any higher you'll almost certainly wreck the comm.


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## bob635 (Dec 19, 2012)

Is there a controller that takes a higher battery voltage and puts out lower voltage to the motor?


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## favguy (May 2, 2008)

Yes, the solitons all will, up to about 340v I think, you can then set max. motor voltage


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## bob635 (Dec 19, 2012)

Does the High Voltage Zilla's also do this?

So drag racing electric cars also seem to be running high voltage. 

How do they do it?


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## Ziggythewiz (May 16, 2010)

I think most of the intelligent controllers will do that.

Drag racers use a combination...they overvolt motors till they blow up then replace them and do just a bit less (and it only needs to last 10 seconds).

They also try to provide a pack voltage much higher than the max the motor can handle so that even when sagging up to 50% the motor is still seeing it's max voltage.


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## kerrymann (Feb 17, 2011)

bob635 said:


> How high a voltage can you operate an ADC 4001.?
> 
> We have been running at 180-190 volts and am thinking of going to 250 vdc.
> 
> ...


I am surprised to hear you are running 190V on a ADC 9". Are you running the stock brushes?

I don't know if I have heard of any surviving past 170V, though some warp9s have gone higher. What kind of amps are you running? I assuming you are referring to 190V pack voltage? 

Like Ziggy said, the pack will sag at high currents so if you are running a 190V pack then you are putting a lower voltage to the motor. If you just upgraded your controller and pack to a higher voltage then you might be in for a unpleasant surprise if you set the motor limit to 190V. If it does work I want to see video so I can crank up my volt limit on my ADC.


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## Duncan (Dec 8, 2008)

bob635 said:


> How high a voltage can you operate an ADC 4001.?
> 
> We have been running at 180-190 volts and am thinking of going to 250 vdc.
> 
> ...



Hi Bob
There are several things happening here

Your controller is a power in - power out device
So increasing the battery voltage will enable the system to run with less battery current
Your motor has in inherent resistance - this is quite low so it only takes ~ 20v to push 1000 amps
As it spins it produces back EMF so more volts are required to counter this
Rpm, Volts, Current are "linked" 
At any given Rpm and current there is a certain voltage

SO - the only way for motor voltage to increase is by increasing either Rpm or current

If you are not going to increase either of these your motor voltage will not increase with increased battery voltage 

Of course if you do increase Rpm or current then your voltage will increase

Now this is talking about "motor voltage" - but you cant go silly on battery voltage as the controller is using a mark space ratio system

This means that the motor does "see" battery voltage for a fraction of a millisecond - on for a "short time" - off then on again...

There will be a voltage where this instantaneous voltage will break down your insulation - *I think* this will be quite high, 600v+ - but then I am a mechanical engineer - Not an electrical engineer


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## Tesseract (Sep 27, 2008)

Duncan said:


> ...Now this is talking about "motor voltage" - but you cant go silly on battery voltage as the controller is using a mark space ratio system
> 
> This means that the motor does "see" battery voltage for a fraction of a millisecond - on for a "short time" - off then on again......


Nope, as long as the "mark" time is low relative to the field inductance, the latter will effectively drop a large fraction of the applied voltage during which time the current through the motor will increase. Of course, when the motor is spinning its back EMF also opposes (ie - subtracts from) the applied voltage.


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## bob635 (Dec 19, 2012)

One of the old timers here in Las Vegas recommends advancing the timing on the motor to allow it to deal with higher voltage and speed. 

He used to race an ADC 4001 with 240 vdc PbA.


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## Duncan (Dec 8, 2008)

Tesseract said:


> Nope, as long as the "mark" time is low relative to the field inductance, the latter will effectively drop a large fraction of the applied voltage during which time the current through the motor will increase. Of course, when the motor is spinning its back EMF also opposes (ie - subtracts from) the applied voltage.


Thanks Tesseract,

So essentially you should go for as high a voltage as your controller can handle - and worry about current and Rpm for the motor


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## Tesseract (Sep 27, 2008)

Duncan said:


> Thanks Tesseract,
> 
> So essentially you should go for as high a voltage as your controller can handle - and worry about current and Rpm for the motor


This is correct, up to a point... Switching losses in the controller go up with voltage, and other arcane problems like bearing erosion and insulation breakdown from capacitively coupled currents start to crop up.


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## Duncan (Dec 8, 2008)

Tesseract said:


> This is correct, up to a point... Switching losses in the controller go up with voltage, and other arcane problems like bearing erosion and insulation breakdown from capacitively coupled currents start to crop up.



_*up to a point..

*_What sort of number are you talking about here? - 200v?, 400v?, 600v?, 2000v?


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