Servo drive to drive Vibration Unit

[kiwiavi]

I have a Vibration tester to test electronic PCB's and small assembled units. The shaker can handle 100 volt @ 20 amp RMS. Correct 2 KW. It only has a 0.3 ohms DC coil and most audio amps will normally only work down to 2 ohms.

The frequency range is from 5hz to 2k and I was wondering if a servo drive would work with some mods. I could use an analog to pulse conversion unit to drive it.

Thanks Wallace

[vger]

Wallace,

Ok, here is one possible solution.... locate 4 identical 500 watt amps capable of driving into a 2 ohm load and run them in parallel. This will get you down to 0.5 ohm drive capabliity. The amps must be very well matched and have no DC offset, or all the same small DC offset, and identical gains. If the 0.3 ohms is the DC resistance of the coil, then it's impedance will be just a bit higher with the AC applied. Of course the impedance will be frequency dependant. A Voice coil drive shaker (I assume that is what you have) will have an impedance curve similar to a loudspeaker...
http://www.churchsoundcheck.com/imp1.html
Hope this helped.

Steve