## Motor Question

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• The Sparrow motor is rated at 150V. I have used 14 batteries at one point - 168V. I know the Kilovac controller can go somewhat higher - maybe 180V? My
Message 1 of 2 , Nov 1 8:11 AM
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The Sparrow motor is rated at 150V. I have used 14 batteries at one point - 168V. I know the Kilovac controller can go somewhat higher - maybe 180V? My question is... what allows an ADC motor to go over it's voltage rating. And just how high can it go? Or this really all about RPMs?

Matt Wilson
#159
• ... What you are forgetting is that the motor is NOT connected directly to the battery pack: there is a motor controller in between. The motor controller
Message 2 of 2 , Nov 1 8:23 AM
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> The Sparrow motor is rated at 150V. I have used 14 batteries at one
> point - 168V.

What you are forgetting is that the motor is NOT connected directly to
the battery pack: there is a motor controller in between.

The motor controller _lowers_ the voltage and _raises_ the current, by
an amount set by the present conditions. The motor controller works like
a step-down transformer, except that it works at DC instead of AC.

> what allows an ADC motor to go over [its] voltage rating.

It never does.

> And just how high can it go?

Like the man said: 150 V.

> Or this really all about RPMs?

Yes, RPM does have a role to play in this equation.

Roughly speaking, the voltage across a DC motor is directly proportional
to its RPM. (More precisely, it is somewhat higher than that, in order
to generate torque.)

The motor controller takes the full pack voltage (156 V nominal) and
drops it down to the voltage that the motor needs at that RPM. So, when
you're stopped, the motor voltage will be just a few volts, even though
the pack voltage is about 156 V. When you're going at highway speed, the
motor voltage may by 50 V or so, even though, again, the pack voltage