Series motor needed 1

[insideman]

I have dredged and Googled vigorously, but have not come up with a suitable motor. I need a 120VAC motor with easily varied speed and maximum power about 1/2 hp at 5000 rpm.

Any thoughts?

 

[jraef]

A Sears circular saw? They turn at 5000RPM. They are not variable speed, but they are universal motors (AC/DC) meaning that they can be varied by reducing voltage with a rheostat or SCR controller.

http://www.sears.com/sr/javasr/prod...vertical=TOOL&pid=00910831000&tab=spe#tablink

"Venditori de oleum-vipera non vigere excordis populi"

 

[itsmoked]

Nice idea jraef!

 

[insideman]

I don't think swiping a motor from a saw will serve me. But thanks for the thought.

 

[itsmoked]

Okay then the Vacuum Cleaner must die!

 

[itsmoked]

You want to spend some denaro? Then you buy a gear box, or pulleys and a three phase motor, and use an VFD to run the motor. (Can be single phase.)

 

[insideman]

Itsmoked: Sorry, no cigar. Must fit within the hub of a high speed fan.

Pat

 

[jraef]

Do you need just one for a project, or are you designing a product and need it as an OEM? If the former, I doubt you will find an off-the-shelf high speed motor like that without "swiping" it from something else. If the latter, since it is already obviuos that they are made, I would go to the manufacturers of like systems, such as Emerson Electric who make the saw motors for Sears, and ask them for help.

Just because you can't find it on Google does not mean it cannot be done.

"Venditori de oleum-vipera non vigere excordis populi"

 

[benta]

You could check out Johnson Electric,

http://www.johnsonelectric.com.

They have both HVDC and Universal motors.
Problem is, the universals run anywhere from 20000 to 40000 rpm, so you need a reduction gear.
When you look at the portable power tools like the Sears saw, they actually use high speed universals with reduction. They use the same motor without reduction for router, for instance.

Regards.

 

[insideman]

Thanx Benta.

Johnson was a good clue. I rechecked my fan calcs for 20,000 rpm-Pitch becomes too low to be practical. But I can go with a larger hub diameter, which eases the pitch problem.

Would still like to find one at 5,000....

 

[benta]

I checked at Johnson.
The closest to your requirements is a HVDC (120 V) delivering about 200 W, which is a bit below what you are looking for. However, with a bridge rectifier in front of it, it would be an easy solution. Johnson part number is HA03005.

Regards.