identifying proper motor

[mikdandn]

Hello all. We are working on a project and have hit a problem. We are building what is essentially an electric seesaw or oil rig. Currently we are using a 12v wiper motor mounted to a pole. The motor is attached to a horizontal bar using a drive arm. The horizontal bar is approximately 4ft long. The weights at the end of the bar are approximately 5# each. We have tried a couple of different wiper motors but the problem we have is that the motor goes into a speeds up or goes into afreefall as each end is descending and gets below the midpoint. What style of motor or set up can we use to keep a constant controlled motion throughout the cycle? We are wanting around 45rpm, give or take, that we can use a controller to vary the speed. Ideally, the motor or device would be reasonably quiet and the overall cost would be less than $150.
Thanks in advance
Mike

[Kelly_Bramble]

Search the internet for:

Constant speed AC (or DC) Motor
Variable Speed Electric Motor and Controls
Adjustable Speed Motor

[mikdandn]

Thank you Kelly. I will do that.

[Hudson]

Another option is a stepper motor. You have 12 Volts. You'll need, in addition to the motor, a driver that regulates D.C.direction and power to the motor coils to determine position and motion plus a pulse generator (probably driven off 5 volts from the driver) that steps the driver through successive motions. The frequency of the pulse generator is your speed control.