Switch gear for 2 speed motor

I have a Colchester Bantam, with a single speed motor. I am looking for a 2 speed motor for it, and want to be prepared, so need to find out about how to install the switching.

My manual, downloaded from a website, does not include a wiring diagram for a 2 speed motor. I also have no idea what switches I need to order.

I would be grateful if anyone can help.

Tom.

Tom

If you go to the link below and press the JOIN button there is copy of the wiring schematic in the parts manual, and a lot of other relevant information that you may find helpful.

**LINK**

Emgee

Use the following after joining

https://colchesterlathe.groups.io/g/main/files/Colchester%20Bantam/Bantam%205%C2%BD%22%20%28140mm%29%20Manual/Bantam%205%C2%BD%22%20%28140mm%29%20manual%20-%20Installation,%20Operation%20and%20Parts%20list/Bantam%20Manual%20Installation.pdf

Edited By Emgee on 17/08/2020 15:47:55

Thank you very much Emgee for your help. That is an amazing website which will give alot of information.

Implicit in your request is that you are seeking a three-phase two-speed motor. Are you aware that two-speed three phase motors are difficult to run on 230v three phase (i.e. you need full fat 415v 3-phase. The semi-skimmed low voltage version will not do)?

I believe that Tom said in another thread that he had a 3-phase supply available.

Andrew

Are you looking at 2 Speed Single phase motor or 3 Phase 2 Speed Motor or Maybe a inverter drive motor .more details are required .

Bee M

Sorry Brian. I ve had a busy 2 days. My motor will be a 2 speed 3 phase motor. But I am replacing a single speed 3 phase motor, so dont have the correct wiring/switch gear for the 2 speed motor. I would like advice as to what to buy and how to connect it.

Thanks, Tom.

This is the plate off the 2 speed motor.

Although I will get my elecrician to do the wiring and connection, I would like to understand what needs doing, and also buy and mount the switches "first fix".

Why not just fit an inverter and have done with it?

I believe from a previous post Tom as got a VFD but despite a number of members suggesting he leave his VFD fitted Tom seems to want to fit the two speed motor he's got !

Hi Tom ,

I guess your motor has 6 Terminals for connections 3 for low speed and 3 for high speed Your Motor has 2 sets of windings One for Low , and one for high speed , You will need a three phase control panel that allows a complete disconnection of supply from low speed that allows the motor to stop , Before you switch to high speed ...

Your Electrician will be able to sort this out for you..

A 3 phase changeover switch may work I position for low speed and the other for high speed . Dont Switch from one to the other before the motor stops

Good Luck Brian

Thanks Brian, I dont think there will be a problem waiting for the spindle to stop before changing speeds, because the speed is chosen for the job, and not continuously changed.

The main reason for not going down the VFD route was that I want a higher chuck speed than the inverter delivers.

Tom

I believe you will find a pole changing start set-up is needed if you have an original type 2 speed motor, all windings are used for both speeds, similar to Dahlander circuit.

Emgee

Tom

Your motor Data plate shows 3 Phase and voltages for 3 phase , I think you will have to ask your Electrician without being able to check this motor and test , there are a few questions that raise alarm as a three phase motor that starts to run on 2 phases sounds incorrect . Once you run this motor all questions will be answered amperage loadings will all be the same for each phase and may change depending on the speed that you a running the motor free from any load .

Regards Brian

OK MG and Brian, you are making me think I need an original Colchester wiring diagram.

The 2 speed motor I have bought, its plate is the one I posted, is off a Bantam, so I know it was built for the application.

I am not good at electrics, so will pass on your comments to my electrician. Will try and dig up a wiring diagram.

Im enjoying this, its just out of my area of knowledge!

Brian: I don't understand your last post? In my experience running a 2-speed motor on a 3-phase supply (which Tom has) works just fine. I'm not sure where starting on 2 phases comes into the picture?

Andrew

Tom

If you use the 2nd link I posted that takes you to the Manual showing on page 8 an electrical schematic for your electrician.

Emgee

I found a coupe on flea bay. Here is a link.ebay.com/itm/Milling-Machine-Part-New-Forward-Reverse-Switch

I purchased one The contacts are rather small so I suspect life will be short if switched between fwd and rev as in tapping.

Good Morning Tom,

I have a friend, who, about five years ago replaced the two speed motor with a single phase motor, and he gaave me the old motor. So, if you want a spare, pop round and pick it up! Airfares may be expensive!

From your motor nameplate photograph, you have a two pole / four pole three phase motor. The easiest solution, if you can't source a switch, is to install two contactors with electrical and mechanicaal interlocks that will prevent both contactors being energised at the same time.

Regards,

Alan.