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Wiring a single to 3-phase inverter.


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Got my inverter today ( technical-looking thing it is too). It comes with comprehensive instructions, that us mere mortals can't understand at all, so I'm stuck and hoping that someone on here will be able to tell me what wire goes where. There are just three red wires and an earth coming from the drill, then a normal 240v A/C 13-amp supply. I stripped and cleaned the drill on Sunday, so I'm keen to get it connected without involving any of the emergency services/frying my delicate bits.

Pics of the unit and obvious connections (I can supply more info if required).

Thanks very much :)

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Les.

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With regards to the supply, it says -

'L/L1, N/L2 and L3 (R,S and T): AC supply line 200-240v models (except 7.0a and 16a) can be opertaed with two phases (single phase operation) without current derating. In this case, the AC supply can be connected to any 2 of the 3 input terminals.

Les.

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U V W are the motor windings, it looks like the inverter is mounted on a filter, is that the case? If so, i'd expect that the blue and yellow wires are supplying the inverter from the output side of the filter, is that so?

You will need L and N and PE through the filter, and then L N PE to the inverter. your first picture shows L N and (seperate) PE connections.

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'L/L1, N/L2 and L3 (R,S and T): AC supply line 200-240v models (except 7.0a and 16a) can be opertaed with two phases (single phase operation) without current derating. In this case, the AC supply can be connected to any 2 of the 3 input terminals.

Yes, the phase - phase (or phase - neutral) AC voltage will be rectified to DC inside the inverter. you will get a lower DC bus voltage P - N than P - P

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Well a partial success, no bangs, ambulances, etc :)

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Fiddled with the control panel a bit until it beeped, and then raised the number progressively as in this picture -

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When I press the start button on the right, the switch box just buzzes - no click and no drill either ( the motor turns quite easily by hand) :(

On further investigation - When the inverter is on, these three wires that come from it are all live.

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These however, are dead - all the time (they go to the motor, the lid kill switch, and the foot switch)

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I take it this is a solenoid? it twitches when I press the start button, but I think it should fly up and make the connection?

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Not sure about this - looks like it moves and provides the current to the motor (with the power off, I can pivot it quite easily, though it is spring loaded, but I can't push the solenoid up with the power on or off - it is loose though).

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I'm thinking that the start switch mechanism is faulty. Can they be dismantled and repaired, or should I just buy a new switch?

No electric shocks so far :)

Les :)

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I'd junk the original switch and wire the inverter direct to the motor, either use the inverter controls or add on/off switches to control the inverter, and use the foot switch to switch a stop/fast ramp-down on the inverter, which is a function i would expect it to have.

you could use the original switch to switch power to the inverter, if it can be wired that way.

The inverter should have a 'quick commisioning guide' or similar, that will guide you through the parameters you need to set. Sorry, I'm not familar with WEG inverters. you said you were raising the number, it looks like you were just cycling through the parameter numbers to me, hence the P. The manual should contain a list of the parameters and what they do.

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Les, you can't have a switch inbetween the inverter and motor, not sure why, just know from experience from when I wired one up for my milling machine. Wire directly to the motor and then use the on / off on the inverter or just switch off at the 13amp socket.

Chris

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Any motor over 1.5 Kw should have circuit overloads to protect the motor,

I'd say the starter has a 415v coil on the contactor, altering the frequency is screwing up the voltage required to pull in the main contacts,

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The coil of wire is a overload, it heats up with the current, the bi-mettalic strip heats up, pushes the bar and opens the coil circuit, which open the contacts and cuts the supply before the motor burns out/cables start melting :D

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The motor should be wired direct to the inverter. Use the inverter switches to start and stop.

Now get a grownup to read the manual and explain how to drive it.

All the start, stop and protection functions of the original motor starter switch are built into the inverter. The motor protection function may need adjustment, hence the need for a grownup.

jw

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Well I'm grown up (just because I don't know - doesn't mean anything at all) perhaps you are a baby in some circumstances?

Anyway, all is working fine now - thanks mostly to Luke and Al (thanks chaps :) ).

I removed the drill switch mechanism and wired the drill directly to the inverter and use that to control motor speed, dead stop braking, etc. I fitted a 13 amp fused switch before the inverter, and used the drill switch casing to contain the motor connection (15 amp chock block connector and continual earth).

I'm surprised how quiet the drill is - just a slight whine. Bought a chuck key for it yesterday and just need to anchor bolt the base to the shed floor.

35-year old drill and it still works perfectly (took about 4-hours to clean it though :( )

Total cost was-

£100 for the drill

£50 for the inverter

£5 for the chuck key

£8 for 1 gang 16mm pattress box, 13 amp fused connection unit, and 15 amp connector strip, 3m cable.

£163 - absolute bargain :)

Now about that lathe...............

Les :)

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