3 phase motor on single phase.?

[Jixer]

I bought an old impeller fan for dust cottection.
The fan has a 3phase motor, so I thought it would be an easy swap to a single phase motor.
But..... the old motor has a 20mm shaft!
Looking at motor catalogues, 2.2kw motors have 24mm shafts!

I‘m looking at options.
Run this old motor on single phase, is that a good option?
Have the impeller bored out to 24mm + new keyway? The impeller boss is 40mm O/D.
Have a 24 to 20mm step down shaft made, (possible imbalance/cantilevered load on motor bearings)

Anyone seen a 2.2kw single phase motor with 20mm shaft? It’s wierd.!

thx
jixr

 

[6ply]

You can run small 3 phase motors on a single phase supply by adding a capacitor but it's unlikely to be suitable for a 2.2kW motor.

 

[6ply]

Why not just buy a VFD?

 

[Chippie]

2.2kw vfd….££££…. For a decent make…

Look up Steinmetz circuit…..
Using a cap will only yield about 60-70% power….
You can calculate the capacitor value by using the formula:


C = 50 x Hp x (220/V)^2 x 50/f where:

C is in microfarads

Hp is the motor's rated horsepower

V is the motor's rated voltage

f is the motor's rated frequency

Still cheaper than a vfd….

All of this is academic if the motor can’t run on Delta…

 

[Dcal]

A cheap vfd would be my choice as it will give you speed control.

Problem with a fan is the motor is under full load from start up.
With a vfd you could ramp the speed up slowly and give the motor an easier time.

 

[Jixer]

OK thanks I will look into the vfd

 

[Chippie]

OK thanks I will look into the vfd

You need to check the motors label to see if it can be wired for delta….
A vfd with 240v in/415v out will be a few bob compared to a vfd with a 240v output..

 

[Turbo]

You could machine the 24mm shaft on a new motor down to 20mm & recut the keyway.

My vote would be a vfd, cheaper than a motor & will make the fan much more useful with variable speed.