The Shop > Tools
That suds pump.
hopefuldave:
Funnily enough Phil, I think I do... I'll try to dig 'em out, but it's not that hard to work out - when you take the cover off check for a set of 4 big reservoir capacitors (if your VFD is the same as or similar to mine, they're under the main (not the upper logic) board on the lower left, it's fairly obvious which are their leads coming through to the solder side), they're arranged as two parallel pairs in series with a PCB trace where the pairs are seriesed (is that a word?), there are two fairly hefty bleed resistors which also join on the trace you're looking for, you should be able to spot where the capacitor leads come through the board - this is where you want to put the neutral lead, I put a small brass bolt and nut through the PCB (had to drill a hole!) and soldered both sides, then soldered a 1/4" blade (Lucar) connector to the sticking-up bolt to take a crimp connector. The live i brought into L1 (I think) and then jumpered to L2 to give the rectifier an easier time.
If you're not 110% with electronics, find a radio ham / hobbyist to at least advise, you'll be creating some serious voltages in there! This is a simple voltage doubler - the full mains voltage is applied to the two banks alternately so the pair of banks charge to double the RMS voltage (about 480v under full load) or maximum to double the peak voltage (getting on for 700v) under no-load conditions. Fortunately the ACS300 series (those I've seen) have a delay circuit that puts a limiting resistor in series with the supply until the caps are charged to close to their running voltage, so there shouldn't be a big surge on switch-on.
The ripple current on the caps is increased quite a bit so the reservoir caps may not last as long as intended - if you start seeing undervoltage trips at full load it may be time to replace 'em! Also, if the VFD hasn't been in service/powered for Quite Some Time it's worth wiring a 100W bulb in series with the live and allowing the caps to re-form, or even better to slowly (stages over 1/2 hour or so) raise the applied volltage, using a Variac or similar starting at e.g. 90 volts without the motor load attached.
The one I'm using at the moment is the ACS301-4P9, which is rated as a 5HP VFD so plenty for my 3HP motor, which ABBs do you have?
awemawson:
Dave any chance of a simple before and after sketch of that bit of the circuit diagram?
I assume it's forming a single stage Cockroft Walton doubler ?
philf:
Hi Dave,
This is a photo of the main board in one of mine:
I have an ACS 301-4PI-3 and an ACS 311-4PI-3.
I'm reasonable with electronics (I wouldn't rate myself at 110%) but can follow circuit diagrams.
Neither have been powered up for years. I have a big variac so will power them up slowly as you suggest but I'll wait until after I've drilled any holes and done any soldering. (I've been "stung" by a capacitor before and don't want to do it again. It was in a compact camera I was looking at for a colleague and I managed to short out the flash cap with my finger. I flung the camera across the workshop and ended up with two deep holes burnt into my finger.)
Cheers.
Phil.
John Stevenson:
Been asked to pass this message on from Ian Holdsworth AKA 'Circlip@
Sorry it's a bit convoluted but can you get a message to David D on MM forum posting of "That suds pump" to make sure that he actually has got a three phase motor on his EMCO milling head! Trouble is, although the lathe may be three phase the Head may not be, Emco drawing is a bit obscure, I often wondered if they used the same motor for both variants but just added a start Cap. for the single phase. Problem is, for both types the wiring digriam shows a STAR connection motor. Other problem is, if he puts 415 across it and it is single , the bang means a rewind as gen motors are like hens teeth and the motor is part of the construction.
DavidA:
John,
I think he means me , David A.
Pass on my thanks to Ian in case he doesn't see this.
I agree the wiring details for the Emco attachment are a bit obscure in the Denford manual.
I'll re check everything but I'm fairly sure the plate says 415 volt.
It is connected to the lathe via a dedicated socket on the cabinet. And as the lathe is 415 Volt 3 phase I suspect that the attachment would be the same.
Dave.
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