Bridgeport – Adcock and Shipley – UK

[boringtoolParticipant @boringtool]

Hi,

Ive just purchased a Bridgeport Mill (3 Phase), i tried it at work on a 3 phase supply and the Spindle motor worked fine by pressing the ON button first then the spindle switch which rotated the spindle fine, i’ve installed it at home now using a rotary Phase Convertor fed via a 240 supply through a C curve MCB as advised by the RPC supplier. there are 400V at the output to the machine though when the spindle motor is switched to ON the spindle motor the spindle turns slightly but will not run until i press the ON button and hold it in for a second or two, the contactors stutter then it fires up. it doesn’t seem healthy for the contactors and was wondering if anyone here could give me some directions in getting this fixed.

Many Thanks

[Anonymous]

Can’t help directly as I run my Bridgeport from a 3-phase supply. Do the contactors chatter or just hesitate? A chattering contactor implies dirt on the pole pieces. On my Bridgeport I think the contactors are enclosed, but I have had problems on other machines with open contactors. Hesitation implies a coil voltage on the low side. Try measuring voltages under load.

Bridgeport electrics have a reputation for being rather sensitive to the incoming supply.

Andrew

[Swarf MakerParticipant @swarfmaker85383]

I suspect that you need to rotate the phase connections. The contactors are probably being energised from the weakest phase from your converter.  Just move each phase connection around by one position on one of your connectors.

[noel shelleyParticipant @noelshelley55608]

Another thought is the suge current ! I had an issue with a 3Ph generator on one item that was powered from it. one had to hold  the ON button in for several seconds as the voltage would drop below the point at which the contactor would stay in – The contactor would connect for a split second giving the motor a kick and each kick gained speed until the voltage drop recovered and it would hold and the big circular saw would run. During this proccess the contactor would chatter loudly ! Your converter may be to small to start this machine – may be try a  star delta starter. I found that a star delta would easily start the much bigger 11Kw motor on another machine. Generator was 20KVa. The voltage DURING starting is what you need to check, on a good meter that can follow the rapid changes. Good Luck. Noel.

[Chris CrewParticipant @chriscrew66644]

I would be interested to know if you cure the contactor chattering problem and how you achieved it. The reason being that I run a J&S 1310 cylindrical on a rotary converter and the contacts for the wheel motor always chatter but the motor runs up to speed after a stuttering start. I have no idea what the output of the converter is as there is no data plate on it and I was told by the chap from whom I bought it that it had been made in the special effects department of Hammer Films for a location where a 3-phase supply was required but not available. All I can say it that it seems to handle all four motors of the grinder with no problem but I always start them in sequence, wheel-head, work-head, hydraulic pump then coolant and stop them in the reverse order. Non of the other three contactors chatter when the wheel-head is up to speed so I assume it is a characteristic of the output of the converter that causes the chatter, although Noel Shelley seems to have explained what may be happening in my case as well.

[FulmenParticipant @fulmen]

I would try rotating the connections per Swarf Maker’s suggestion. My A&S Bridgeport has all the contactors and electronics wired to a single phase, the only things using the 3.phase are the main motor and coolant pump.

[noel shelleyParticipant @noelshelley55608]

Hi Chris, have you experimented with starting the functions in a different sequence wheel motor last ? the smaller motors may act as a cushion or pilot motor ! The wheel head will be a bit like the saw bench – it takes a bit of spinning up. In my case having started the saw I could then start the 11Kw star delta fitted unit as well, the generator being able to run them both, it was the drop using direct on line starting that caused the issue ! Fulmens comment indicates that the contactor coils are 240V as opposed to 415v ? And having Neutral available ?   Noel.

[Dave SParticipant @daves59043]

I had a very similar issue with my TOS FNK mill. The contactors in my case are wired across 2 of the phases IIRC (no neutral), and I had wired them onto the generated phase, which dipped sufficiently them at they wouldn’t hold in during start. Swapping the wire around sorted it.

 

[BazyleParticipant @bazyle]

See if the contactor will pull in using 240v. If so just wire it up on its own supply.

[FulmenParticipant @fulmen]

@Bazyle: That’s basically the same thing as swapping the wires. The output of a RPC is pretty much the original single phase plus a generated third phase. It should be possible to identify the original phases as they should read 0V (or very low) between input and output.

[boringtoolParticipant @boringtool]

Hi Everyone

Fantastic responses there and i’d like to thank, Swarf, Noel, Chris, Fulmen, Dave S, and Bazyle, for the time spent reading and responding to my post.

As I am Electrically challenged I’m going to print off the responses and ask an Electrician to come round and try again starting with Swarfs suggestion of moving the connections round.

 

Really appreciate the advice, and I’m glad I joined this group.

 

Cheers

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