Hiw to choose DC motor

[jestvall]

I´m in search of a DC motor. Here are some of the requirements.
Initial torque of 78Nm
Effect/power of 34W
As light weighted as possible
Compact as possible
Maintenence free
I don´t know if I need a servo motor, PM motor or something else.
I have almost no knowledge in electronics and mechatronics so I really need some help.

 

[leonar40]

Check this out.

http://www.motionnet.com/

It's an engineering directory that lists companies over a wide array of motor and other motion catagories.

 

[sreid]

You might take a look at Aveox.

http://aveox.com/

 

[benta]

jestvall, your information is very sparse.
However, one of your points is "maintenance free", which points in the direction of either brushless DC motors or stepping motors, depending on application.

Regards.

 

[Barry1961]

I think what you looking for is a 34 watt DC gear motor. Some where around 900:1 reduction. This will give you around a 2 rpm output.

The torque is high for that size of motor(1/30th HP). You could do it with AC voltage with a little Brother gear motor. This would be no maintenance and very compact.

http://www.brother-usa.com/gearmotors/

The high efficiency and high torque is going to really limit your choices. If you really need that much torque with that small of a motor. You may be able to find a very small planetary used in the automotive industry for sun roofs that would work. I don't know a link to a site or how you would get the specs though.

What is the duty cycle of the initial torque and the required output rpm?

Barry1961

 

[blacksea]

If Barry's suggestion with 34 watt DC gear motor is correct, that problem maybe with gearhead. For example, Maxon gearhead with moment up to 120Nm would be used with 250W or 400W motor only.
See more details in

http://www.maxonmotor.com

 

[Barry1961]

If the duty cycle is low enough you might be able to use one of those little "Crouzet" type gear motors they use in small medical pumps and vending machines. They would not be rated for near the torque you require but they might be able to take a few shock loads before failing. You could even spike the voltage to the motor to get that initial torque.

The automotive supplier I was thinking of was Globe Motors.

http://www.globe-motors.com/home.html

But it does not look like they go up that high in torque so it would be the same as a Crouzet, no warranty. Oriental, Bodine, Bison, Leeson and "Grainger" also makes the small med to light duty gearboxs.

There are only a few companies that make that small gearbox with that high of a ratio that are rated for that much torque. Most are torque limited by the gear train with some even having plastic gears on high speed side. As far as I know everyone who makes small industrial duty gear motors use AC motors.

I did a automobile application that required a high reduction, high torque and small power gear motor and ended up using a Brother gear motor and a 12VDC to 120VAC inverter. You can get a converter for your application for under $20 if you have 12VDC at.

http://www.dcacpowerinverters.com/12_volt_power_inverters.html

Barry1961