Need Electric motor advice for test setup

[chadzeilenga]

Hello all,
I am planning on constructing a test setup for work that would involve the use of a rotational electric motor to turn various small gear dampers.
This test would be used to test accelerated life testing and would rotate the small gear dampers (which are the size of about a quarter) in one direction and then reverse in the other direction. The diameter of the gears on the dampers is about 10mm. I would put about 10-20 of them around the OD of a large gear attached to the motor. The torque required of the motor would be at most 56 in-oz's.
What type of electrical motor should I be looking for? This will be operating on an AC circuit. From what I have read I should be looking for a stepper motor. Is this correct. I would like the motor to fit inside of a box that is 6"x6"x10". What should I use to control the rpm of the output shaft? I would like to keep this setup as simple and compact as possible.
This motor also needs to operate in temperatures that range from -40°C to 90°C.

 

[Skogsgurra]

If your speed is allowed to vary and your acceleration isn't critical, then a small geared DC motor (Maxon, Portescap etc) seems to be ideal.

They are much easier to use than a stepper motor (a simple DC source and a few relays/limit switches is all you need). They are generally also smaller and produce less heat.

If you want to make things more elaborate, you can use a micro-PLC (around USD 100) to control the motor. It will then also keep track of number of cycles.

Gunnar Englund

http://www.gke.org

 

[nbucska]

I need more info!!!
I assume you need only one tester so the reduction of the
engineering effort is crucial, part cost is less important.
I would use PC or compatible micro ( or board == $50-$150)
and simple interface. If you need screen and keybord use
a PC- cheap, replaceable, etc.

Stepper motor [I abbreviate SM]is easy to drive if it doesn't have to be
too fast. Position sensor is not needed except perhaps a home position sensor.

The [SM]'s resolution is limited, usual step around
1-3 degree. Microstepping costs more, limits speed.

For other application an analog servo may be the better choise.

Can you tell me the number of motors, their speed,
resolution, torque, etc. (max/min) ?

Some data about the devices they are suppose to
drive.


<nbucska@pc33peripherals.com> omit 33 Use subj: ENG-TIPS
Plesae read FAQ240-1032

 

[MikeHalloran]

So, you want to oscillate a bull gear back and forth a few degrees to exercise a multiplicity of small pinions and the rotary dampers attached thereto. Is that right?

Big gears in fine pitches get expensive real fast. I'd be inclined to use a gear of infinite diameter, i.e., a rack, oscillated linearly. Actually, I'd use a bar, with multiple short pieces of rack bolted to it.

I'd use a screw to translate the bar, and I'd probably drive that with a servomotor. Stepping motors are notoriously hard on mechanisms. I like to use them, but if the dampers are not intended for use with steppers, you may get unrealistic life data.

How do you detect failure or end of life of the dampers? Do you need to measure the reaction torque of each one?



Mike Halloran
Pembroke Pines, FL, USA

 

[itsmoked]

You may want to check Slo Syn synchronous motors. They aren't even vaguely like the standard steppers and they turn slowly by design.

They run at like 72 RPM and run from 70 to 1500 in-oz

http://www.slosyn.com/Sections/Prod...000&L3=&L4=&L5=&L6=&L=False&lang=1&IT=Descrip

 

[waross]

You could check your local commercial refrigeration supply house for a small three phase fan motor and drive it with a VFD. You can power the VFD from single phase.
My very old Grainger catalog. shows three phase motors as small as 1/4 HP.