4 pin converter 5 pin machine

[tangogeko]

So I’ve bought this converter but it only has 4 pins and can’t plug it in. Not really sure what to do.

I can wire it in delta a bit of pain to get to the motor and don’t want to take it out

What are my options?

Or is it a loss cause and worth investing in a rotary converter?

 

[Sideways]

A 3 phase motor needs L1, L2 and L3 connections and an earth (4 pins, 4 wires).
It is a balanced load and it doesn't need a neutral.
Even if wired star, the star point should have a net current of zero and doesn't need to be wired to anything outside the motor terminal box.
That's a good thing for 3 phase converters because basic transwave types and modern digital phase converters generally don't provide one.
Potentially a rotary converter could. Doesn't have to, but might.
Some machines need a neutral but this isn't for the 3 phase motor, it's for a worklight or some other funtion of / attached to the machine that wants a 240v supply and it gets this from tapping into one of the phases and neutral.
It might be for a motor starter if that has a 240V coil and needs to use one phase and neutral to operate the contactor and provide piwer to the motor.
But they make starters with 415v coils specifically so that the coil can be powered from two phase wires without needing a neutral, so this isn't an insoluble problem.

Wiring star or delta depends on the motor and the voltage.
Typical dual voltage motor should be wired star on 415v and delta on 240v three phase.
You don't say what voltage your converter outputs or what voltage your motor is made for, but don't take a dual voltage motor like the one above, change it from star to delta and connect to a converter with 415v out. You'll fry it.

I assume we are talking small motors here and not several kW that requires star delta starting.
Motors like that are designed to operate on 415v in delta config. In star config they need 600 odd volts to run. If you connect them star to 415V, this acts as a reduced voltage (and reduced current) soft start. After a couple of seconds and up to speed you crank a big rotary switch that rewires the motor to delta so it is properly matched to the 415v supply and it can make it's rated power.

So the question is why does your machine want 5 pins ? Does it even use them ? What for ? And potentially changing the plug or socket and just leaving out the neutral might be OK. Your new converter might still drive your machine.

But it's on you. If you don't know what you are doing, get help.

 

[tangogeko]

A 3 phase motor needs L1, L2 and L3 connections and an earth (4 pins, 4 wires).
It is a balanced load and it doesn't need a neutral.
Even if wired star, the star point should have a net current of zero and doesn't need to be wired to anything outside the motor terminal box.
That's a good thing for 3 phase converters because basic transwave types and modern digital phase converters generally don't provide one.
Potentially a rotary converter could. Doesn't have to, but might.
Some machines need a neutral but this isn't for the 3 phase motor, it's for a worklight or some other funtion of / attached to the machine that wants a 240v supply and it gets this from tapping into one of the phases and neutral.
It might be for a motor starter if that has a 240V coil and needs to use one phase and neutral to operate the contactor and provide piwer to the motor.
But they make starters with 415v coils specifically so that the coil can be powered from two phase wires without needing a neutral, so this isn't an insoluble problem.

Wiring star or delta depends on the motor and the voltage.
Typical dual voltage motor should be wired star on 415v and delta on 240v three phase.
You don't say what voltage your converter outputs or what voltage your motor is made for, but don't take a dual voltage motor like the one above, change it from star to delta and connect to a converter with 415v out. You'll fry it.

I assume we are talking small motors here and not several kW that requires star delta starting.
Motors like that are designed to operate on 415v in delta config. In star config they need 600 odd volts to run. If you connect them star to 415V, this acts as a reduced voltage (and reduced current) soft start. After a couple of seconds and up to speed you crank a big rotary switch that rewires the motor to delta so it is properly matched to the 415v supply and it can make it's rated power.

So the question is why does your machine want 5 pins ? Does it even use them ? What for ? And potentially changing the plug or socket and just leaving out the neutral might be OK. Your new converter might still drive your machine.

But it's on you. If you don't know what you are doing, get help.

I’ve opened up the motor box and doesn’t seem to be a neutral running to it. Or running into the box.

There has been this second emergency stop that’s been added to the machine would it power that. I’ve spoken to a few electriains but they don’t really know about working motors is there any other people who might?

 

[Sideways]

Industrial electricians, not domestic installers.

The additional e-stop should be irrelevant.

It could be something as simple as the machine was used in a shop where they had standardised on 5 pin outlets because some of their machines needed a neutral. Any that didn't were still fitted with 5 pin plugs so they could be moved and plugged in anywhere. The neutral pin of the plug wasn't connected to anything if it wasn't needed.

 

[Spectric]

Or is it a loss cause and worth investing in a rotary converter

Those are historic like ring mains and dinosaurs, you need a digital phase convertor which is as good as it gets and the best option is always a proper three phase supply followed by a three phase generator and then the convertor.

So I’ve bought this converter

Make and model would help ? It sounds like you are not electrical so is this convertor even correctly sized for your motor ?

 

[tangogeko]

Those are historic like ring mains and dinosaurs, you need a digital phase convertor which is as good as it gets and the best option is always a proper three phase supply followed by a three phase generator and then the convertor.


Make and model would help ? It sounds like you are not electrical so is this convertor even correctly sized for your motor ?

Motorun is manufacture
It’s it can power 3 kw motor maximum

 

[tangogeko]

Industrial electricians, not domestic installers.

The additional e-stop should be irrelevant.

It could be something as simple as the machine was used in a shop where they had standardised on 5 pin outlets because some of their machines needed a neutral. Any that didn't were still fitted with 5 pin plugs so they could be moved and plugged in anywhere. The neutral pin of the plug wasn't connected to anything if it wasn't needed.

I can’t upload photos as won’t let me but I opened the motor and there isn’t a neutral wired into it

 

[Sideways]

If this chat is anything to go by, a Motorun would be an old Transwave static converter style.
https://www.mig-welding.co.uk/forum/threads/motorun-phase-converter-help.130149/

The problem with those is that an autotransformer is used first to increase the voltage from 240V to 415 ish, and then a bank of capacitors is used to turn it into something resempling 3 phase.

The only time I measured a transwave the output voltage was pretty rubbish. Poor voltage regulation and quite unbalanced between phases. I had a decent meter to measure that safely.

If your converter is an old transwave lookalike, I'd be with @Spectric . Probably not worth it.

 

[Spectric]

That is an obscure make, it seems they are just a small motor repair business and cannot find a website for them. This company has a used one.

https://gandmtools.co.uk/product/motorun-4-h-p-phase-converter-80216092/

If you are replacing that one then look at

https://www.jfkelectricalni.com/product/digital-phase-converter-4kw-5-5hp-240v-in-400v-out/

But think ahead, bigger is going to be more future proof if you might buy more three phase machinery.

 

[tangogeko]

That is an obscure make, it seems they are just a small motor repair business and cannot find a website for them. This company has a used one.

https://gandmtools.co.uk/product/motorun-4-h-p-phase-converter-80216092/

If you are replacing that one then look at

https://www.jfkelectricalni.com/product/digital-phase-converter-4kw-5-5hp-240v-in-400v-out/

But think ahead, bigger is going to be more future proof if you might buy more three phase machinery.

I was gonna go down digital but if I have to change to star to delta it’s gonna be the biggest pain as can’t really get to the motor super well

 

[Spectric]

I was gonna go down digital but if I have to change to star to delta it’s gonna be the biggest pain as can’t really get to the motor super well

With a digital phase convertor you do not have to modify the three phase machine in any way, you just plug it in so saves on any changes o motor configuration.