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DRO killing - Phase converter

zebbguy

Aluminum
Joined
Oct 19, 2020
Right so I have 3 phase in the workshop in a Inconvenient location, boss doesn’t want move it to the other side ; so I have got us a phase converter (transwave 5hp)

Plugged in Harrison m300 lathe
Works fine but dro flashed a blew a cloud of smoke - dead

How did this happen dro was fine before I ran lathe on a phase converter ?

The phase converter is set to 400v
And is wired correctly
 
Not familiar with that brand, quick look at website shows they offer a static and rotary converter, you do not mention which type you have. Wild guess is that you powered dro with the artificial leg, but you also do not mention what voltage the dro is. Post more info, you might get more info.
 
I second the thought that the DRO was powered by the generated leg. With a RPC you need to be sure the two line power wires that pass through the RPC are the ones that power anything other than the motor(s). The generated leg voltage can be very high, especially before the motor is ran under load to bring the voltage down, that is normal.
Sucks you just leaned the hard way though:confused:
 
As The above two state, the DRO would have been 240V and run from one phase to neutral. Even on the rotary converters (which the 5hp should be) you need to run any single phase/phase to neutral loads from the connections that are common to the mains, since the other two phases will have voltages that can be a long way from 240V. Transwave don't seem to state which phase is connected to the input, but if you phone them they will be happy to tell you (I think!).

Aha. Found it! :-
Transwave said:
The MT converter can accommodate both a 415v
control circuit (as above) and a single phase 240v
control circuit provided the L1 phase is used in
conjunction with the output Neutral.

You've got a DRO with missing maginc smoke, but the above should help prevent e reocurrence.of the problem. note that the same applies to any other control circuits, like contactors or relays in the machine's electrical box.
 
Is electrical work really expensive over there or is this a really big shop? I can't imagine running a rotary if I had 3 phase in the building.

The cost of that phase converter had to be in the ballpark of real 3 phase unless a new panel was needed.
 
Probably the static type, which for that company seems to be one involving a transformer and capacitors. Possibly the Steelman method?

Anyhow, those may not produce the correct voltage unless loaded, so NEVER connect ANY single phase loads to the "made" leg of a phase converter.
 
£2000 was the quote is it rather a awkward job, i realize the sparkie is just trying to pay for the next holiday to Greece. Not worth arguing over the second hand phase converter came it at £250.00
 
Sorted -----

So i pulled the power supply out of the DRO, my college eagerly noticed that it was 5V - 1a



So i did some less than adequate soldering...............

Its now running from an android charger I found which is 5v - 1a max - seems to be working fine! :D (plugged into a wall socket)

Beats the £300 replacement unit I found


Yes i think it was running from a badly wired generator leg (doesn't explain why it was ok on the dedicated 3 phase supply though)
 
..............

Yes i think it was running from a badly wired generator leg (doesn't explain why it was ok on the dedicated 3 phase supply though)

Power company 3 phase is quite stable in voltage. Powerco has to keep it in tight regulation, 10% high is max, and most want to keep it under 6% high. For you, maximum is 264VAC on 240VAC.

The "made" leg can be all over the place, from quite low, to almost double rated voltage.
 








 
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