# Servo drive - power transfer

Thread Starter

#### Skeebopstop

Joined Jan 9, 2009
358
Dear All,

I am thinking of a situation where a DC Bus is in a phase of rectification where the reservoir capacitors are driving the entire output power.

The DC Bus over this ~10mS period drops linearly by 80V at a capacitance of 1360uF, from 350V to 270V.

i = c dv/dt -> i ~= 11A

Am I correct in assuming the DC Bus drove

(350*11 + 270V*11)/2 = Pavg ~= 3.5kW?

Now I am trying to understand how this power is being distributed.

I know some will be losses as resistance in the windings. I realize some will be getting stored up as energy in the inductance.

What I am failing to quantify is how to couple the electrical power, if my calculations above for 3.5kW are correct, and the mechanical output.

Lets give three situations in which to try and explain this:

1. Locked rotor, so back emf is 0.
2. Large load at low velocity.
3. Medium load at large velocity.

This is an industrial based question for those wondering the level.

Regards

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