Choosing an Electric Motor

[CINCINNATI2929]

I am designing a 1-off custom jointer for surfacing wood. I have a cutter head. The commercial jointers that run this head spin it at 10,000 rpm using a 20,000 rpm motor running on 110V.

Should I just select a “conventional”electric motor or is there a more modern updated design that would function better. Would you recommend 2.5-3 HP/20,000 rpm, or should I go with something else and change the gear ratio?

 

[Skogsgurra]

I guess that the 'convential' motor has brushes. That usually means limited run-time before service. A VFD and a 10 000 RPM three-phase asynchronous motor seems to be a much better choice. I have run such motor at around 120 00 RPM. So you are far below what is possible. A small VFD with single-phase supply - or three phase, if available - usually mrans a more stable speed vs load and also lower starting current. And no brushes that need replacement.

Gunnar Englund

http://www.gke.org

--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.

 

[LionelHutz]

You didn't explain very well. Is the 20,000rpm motor geared down to 10,000rpm at the spindle? How?

110V and 20,000rpm does sound like a universal motor which has the disadvantage of brushes.

A 2-pole induction motor can run at maximum speed a little under 3600rpm @ 60Hz, so you need to find some other type of motor or a VFD to run at that high a speed. To run on 120VAC single phase and achieve 20,000rpm will require a specialized motor and also possibly a specialized VFD.

 

[jraef]

Specialized motor, yes, because of the bearings at the very least. But those are just called “spindle motors” and are easily attainable. Specialized VFD? Not really. 20kRPM from a 50Hz base speed is 400Hz, most modern VFDs on the market now are capable of 400Hz output.

3HP in a universal motor is more likely to be made of “unobtanium”. I’ve never heard of one that big. I’m sure someone would make it for you if you write your specs on the back of a big enough check, but why? You can get off the shelf readily available products to do this with an AC induction spindle motor and a VFD.


" We are all here on earth to help others; what on earth the others are here for I don't know." -- W. H. Auden

 

[LionelHutz]

The combination of gearing down from 20,000rpm to 10,000rpm and an induction motor doesn't make any sense either when direct drive or gearing up would make more sense.

 

[waross]

E-Bay

WATER-COOLED-SPINDLE-MOTOR-ER20-2.2KW-SPINDLE-amp-2.2KW-DRIVE-INVERTER-VFD-HY
$319.90
Have one to sell? Sell now - Have one to sell?
Details about WATER COOLED SPINDLE MOTOR ER20 2.2KW SPINDLE & 2.2KW DRIVE INVERTER VFD HY

input voltage:220V±15%(we also stock1.5KW,3KW,4KW,5.5KW,7.5KW inverter,pls contact with us if you need)
Output voltage:220V±15%(Analogous to Input voltage)
Input Frequency:48-63HZ
Output Frequency:0-400HZ
Input Phase:Suit for 1 phase input and 3 Phase input.
Output:3 Phase
Warranty:two years
From a well-know manufactory who manufacture inverter for close to 20 years

OR

TOP 4KW AIR COOLED SQUARE SPINDLE MOTOR ENGRAVING MILLING GRIND FOR CNC $299.00
we also have the following specification for Air-cooled electic Motor

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[jraef]

Bill,
HY (aka HuanYang)... WORST DRIVE EVER!


" We are all here on earth to help others; what on earth the others are here for I don't know." -- W. H. Auden

 

[waross]

For that price, use the motor and buy a decent drive.
Unless the motor is the same quality as the drive.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[zlatkodo]

If you are going to use a standard 50 or 60 Hz motor + VFD, note that not each motor is capable of withstanding the speed at 400 Hz.
This can be very dangerous.
Motor Winding Repair and Design