Electric motor help


(cindy) #1

Hi all I don’t know if this is an appropriate question for an electronics forum but thought I would try. I know there is a wide range of talent and experience here.

I am trying to fix a squash ball machine for our junior program (like a tennis ball machine but just for squash balls). The machine is no longer supported by the manufacturer (sold by Black Knight) and the motor manufacturer has even gone out of business so data is hard to get. There are two motors that work together so I was able to get RPM off the good one. My question is if anyone would have suggestions in locating a replacement (or two ). I am hoping to luck into a direct replacement but I have spent some time on line and that is looking unlikely (although up until tonight, I was looking for an AC motor) . I am open to making minor physical changes, electronic ones if needed…I would hate to write this machine off as it is a great asset for aspiring squash players.

The motor is about 5" long and 3" in diameter. It is labelled as 90 VAC, 60 Hz but is driven by a control circuit that varies the speed. (In typing this, I thought I should see what range the motor is driven in (volts) I found I measured the voltage as 51 volts to 115 VDC…so now I am more confused!)

The other motor spins in the opposite direction, although the same motor. Each direct drives a wheel about 6 inches in diameter and the squash ball is dropped between them, then fired to the court. I measured the maximum RPM on the working motor and it went up to about 3500 RPM and down to almost zero. I have not looked a the control circuit very much yet. It is working well, with the other motor.

Not sure if I am looking for an AC motor or a DC motor with this new info. Are AC motors ever driven with a DC voltage or is my DMM fooling me? On the AC scale, I got about 8 volts, regardless of speed input.

Anyone have any suggestions for me? Thanks