Discuss How to wire motor plug in the Electrical Wiring, Theories and Regulations area at ElectriciansForums.net

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jinsingh, seriously are you going to use this in a business, or for DIY at home?

As far as protective conductors go, the Chinese have weird ideas, I've spent time out there teaching a company to comply with EU requirements.
Their socket outlets are not necessarily earthed, so they fit a separate point to earth the equipment back to an earth marshalling terminal mounted on the wall.

As it stands.
Either way, this equipment is not legal for use in the EU, nor is it legal to import.
If this is going into a business, I seriously suggest you re-think, as the offence is criminal, not civil.
If it is for DIY, just beware that it has been imported illegally, and would be illegal to sell second hand should you feel so inclined.
It would be likely that it would void any house insurance claims if something went wrong.
 
Seems a company called AliExpress market these but the UK site doesn't have them so it must has been obtained outside of the EU.
 
It would be unwise to give advise on how to connect the machine because if it is not earthed it is not safe. Have you purchased it as a new machine or second hand/used.
 
That is a proper lash up, I would send it back as it's not safe or fit for use.

If they have lashed the electrics up what else have they lashed up, I wouldn't want to be near it when that wheel gets up to speed.
 
It is typical of a cheep Chinese import machine.
I would expect it to cost more to bring up to uk standards than you have paid for it.

it also looks as though it may have no means of earthing, although that would have to be confirmed.

I doubt you will find a reputable electrician that will be able to sort it out and connect it up whilst achieving a suitable level of machine safety unless you are willing to pay a lot of money.

I am seeing amongst other things

lack of guarding
no emergency stop button
all signage is in a foreign script so cant be read.
probable that m/c is not earthed
cables do not appear to be going through correct glands
it is undoubtedly not CE marked.

I think you have 2 choices

1. send it back for a refund
2. find a guy down the pub that knows about electric stuff and buy him a beer. (p.s. this would be against my advice and the majority of the comments above)
 
I think it is earthed. The blacks of the supply and motor cables disappear out of shot near the switch, I expect to a couple of tags under some convenient screw. The supply cable has the three Chinese phase colours plus a black earth.

But I like Davesparks' comment which sums it all up, it's pretty likely to be unsafe in ways more insidious that having funky colours in the mains cable. OP, sorry, don't mean to be disparaging, but on here we tend to say it as we see it.
 
Even if you could get this unit to work.

There is a reason surface grinders are not bench tools. The vibration and accuracy need to be compensated for, so usually are quite heavy units.

So I imagine, even if you're willing to spend a large (an it would be large) amount of money to bring it in line with UK safety requirements, the machine probably wont be very good.
 
For the OP: what I have written below is for my electrical colleagues on the EF. You need someone to rewire afresh the whole machine which at the moment is an unsafe lash-up.

I have been studying the images the OP provided and have an alternative view on what has been wired.

Some assumptions:

1. The work lamp is 220Vac.

2. The motor is a three phase squirrel cage motor which can be wired 380V star or 220V delta.

3. The original manufacturer's wiring was for 3 phase operation at 380V and the TPDT centre off rotary switch enables Reverse - Off - Forward rotation of the motor - there are clues to this if you study the rotary switch images, the classic positions of the 4 solid links and the chopped of blue and green wires. The motor was wired as star.

4. I reckon (cannot be certain) but the original machine lead was 3 wire and earth. The lamp obtained its 220V ( = 380/1.713) by connecting across a line and the virtual neutral at the start point of the motor. If the lead was 4 wire and earth then an external neutral is provided which the lamp can use.

5. On one of the specification plate images it says the machine is for 380V, but at the bottom right 'Voltage - 220V needs to be customized and pay extra...'

I think then that the original 380V 3 phase star motor has been 'customized' to run on 220V single phase. The ability to swap motor direction has been disconnected and all the rotary switch does now is switch on/off the L and N to the motor. What the black wires does at the rotary switch I do not know without seeing what happens where it is sleeved with white sleeving - is it attached to the metalwork to be the cpc? For China this would be the wrong colour for the cpc - they use green/yellow - black or blue are reserved for the neutral.

To operate at 220V the motor must be wired as delta. The 'customization' is to attach the black plastic box over the original motor terminal housing and place a capacitor to the left and right as shown. These capacitor are for start and run in the Steinmetz type 2(delta) circuit, where Cr and Cs are what you might expect ie:

How to wire motor plug 1566384258559 - EletriciansForums.net

What you see is a switch which introduces the start capacitor during run up and then disconnects it at operating speed. The grinder motor has no internal switch to do this and the rotary switch cannot be co-opted to do it. The customization overcomes the absence of the switch by wiring the motor as the red circuit drawn below which keeps Cs in circuit . The way winding W is fed via winding V reduces the potential across W to prevent it overheating when permanently fed via the low series reactance of Cs which although its value cannot be seen is normally of the order 200uF. By contrast the run capacitor is 25uF so a higher series reactance. Tracing out the machines current wiring one arrives at the circuit I point to in the middle of this scribbled diagram, where LN are across U:



How to wire motor plug chinamotor.JPG - EletriciansForums.net

I have not had time to think about whether the rotary switch can be used to provide REV- OFF-FWD control - perhaps others might think on this.
 
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