What do I need to know to calculate size of single phase motor?

[pgrbff]

Well a 2kw vfd will cost around £55 off ebay or similar.

It can provide adjustable speed control without having to shift belts in pulleys etc.

It can also soft start to reduce the impact both mechanically and electrically plus a few other advantages.

One other advantage is that to a greater or lesser extent the existing switchgear can remain in place, often when moving to single phase most of the switchgear needs to change.

One other alternative is to use a rotary converter, this takes 230V input and produces a 415V three phase output, you can then use this for multiple machines which then don't require modifications.

My husband uses this to drive his lathe or milling machine, or surface grinder all of which are as they were designed, no mods

Thank you. I thought a quality VFD would cost more. I guess £55 is a budget version? Do I assume from your earlier post that the wiring to the motor, you mentioned 260, would also have to be changed with a VFD? I don't understand star and delta wiring but looking at the the plate I have shown this motor can be wired either way? The machine currently has a 3 phase plug.

 

[Julie.]

Thank you. I thought a quality VFD would cost more. I guess £55 is a budget version? Do I assume from your earlier post that the wiring to the motor, you mentioned 260, would also have to be changed with a VFD? I don't understand star and delta wiring but looking at the the plate I have shown this motor can be wired either way? The machine currently has a 3 phase plug.

I would expect the 260V motor would be ok for 230V supply as is.

Basically a three phase motor has three windings, you can connect three windings like a star - the three supply phases to each of the windings, with all the other ends of the windings connected to a common point, or as a delta - winding 1 between supply phase 1, and phase 2, winding 2 between phase 2 and phase 3, and winding 3 between phase 3 and phase 1 - there will be a connection diagram in the motor terminal housing or somewhere similar.

Yes £55 Would be a cheap and cheerful version.

 

[Steviec1]

From what I have been told the machine could be 50's or 60's. Is it possible to estimate the HP or KW from the info on that plate?

If a vfd is any use I have a eurotherm 650 single phase inverter. As new still boxed.
Input 220-240v AC 10.5A, 1or 3 phase
Output 220-240v. 4A 3 phase
£50.00 postage £5.00

 

[pgrbff]

If a vfd is any use I have a eurotherm 650 single phase inverter. As new still boxed.
Input 220-240v AC 10.5A, 1or 3 phase
Output 220-240v. 4A 3 phase
£50.00 postage £5.00

I think it may be a tad small. I think I need 5A output. But to be honest I don't really know enough to be sure.

 

[Steviec1]

I think it may be a tad small. I think I need 5A output. But to be honest I don't really know enough to be sure.

Hi, 5Amps is the maximum the motor can deliver.
The bandsaw may well tell you what it needs.
Regards Steve

 

[pgrbff]

Hi, 5Amps is the maximum the motor can deliver.
The bandsaw may well tell you what it needs.
Regards Steve

The bandsaw is far too old There is no info I can find

 

[pgrbff]

The bandsaw is far too old There is no info I can find

What would happen if the motor tried to deliver 5A and the VFD was only 4A. The saw is for hobby use and I hope wouldn't be pushed too hard.

 

[pgrbff]

I think it may be a tad small. I think I need 5A output. But to be honest I don't really know enough to be sure.

Can you tell me the model number so I can take a look?