Bridgeport Adcock-Shiply built, mill with Erskine power feed controller driving both X and Y axes

[David Leahy 1Participant @davidleahy1]

Dear All,

I have after 2 years of it being sat there in my garage finally connected up my Bridgeport mill. The spindle runs just fine from the rotary converter I have connected it to. However, no power feed? I looked across the internet and there are several reports on the motors flooding with oil from the small gearboxes they are sat beneath. I checked the motors and all is fine no signs of oil ingress. Brushes slightly oily but hardly any to worry about. I cleaned these and reassembled the motors. Wiring looked OK, I also do not have the coolant pump working it looks to come from the same board? Is this connected to the no-functioning power feeds? I am not much of an electrician but on visual inspection there is no burning visible on the boards? 



When I turn on the power feed switch I hear the realays click over but no activity to the motors? Both X and Y are non-functional?



Any advise here will be much appreciated.

Thankyou.

Edited By David Leahy 1 on 24/01/2018 10:22:22

[David Leahy 1Participant @davidleahy1]

Bridgeport axis power feed problems.

[EmgeeParticipant @emgee]

Hi David, have you checked on the drive card for a RED overload reset button, it may need resetting by pressing. If yo hear a click when pressing it was in overload position.

Emgee

[David Leahy 1Participant @davidleahy1]

Thankyou, I didnt see that but will look for it and try this when in the workshop next.

[Clive FosterParticipant @clivefoster55965]

David

Worth checking the overload button as Emgee suggests but if the contractors are operating its probably OK. Best to verify that they are all working by running with the electrical cabinet door open. Operate the door interlock switch with a big screwdriver or similar so everything runs. Not forgetting to turn it back off before you try to shut the door! Took me an embarrassingly long time to remember that once!

If the contractor throws in when the button is pressed but immediately drops out when released it may well be the auto / manual reset thingy. Normally the contractor overload should reset automatically if its triggered but on the units fitted to many Bridgeport there is an option to select manual reset. Manual mode would be a right pain on a Bridgeport because the door needs to be opened to reset it. When it gets old it can sometimes lock into manual mode despite the switch still being set to automatic so the contractor immediately drops out when the button is released. Cure, on mine, was a good dosing with contact cleaner / lubricant and several operations of the auto / manual switch. If it happens again it will get a new set of contractors, modern DIN rail types. Life is too short to mess with this sort of thing once it gets too old.

If you thing you have problems with the Erskine control board best place to start is to sign up to the Bridgeport-Mill Yahoo group **LINK** where you will find full circuit diagrams of a typical Erskine controller and a typical drive selection board. As far as I'm aware most of the variations between different versions and PCB numbers are component level, different type numbers for active devices and minor changes in passive ones. The basic circuit seems to be common. The set-up and considerable functional check information is also in the group files. About the only thing missing is specifics on the pulse transformer. Which, unfortunately, appears to be one of the more common failure points. So if anyone out there has the data for that …

Should be enough there to get started if you have a mate knows about electronics.



If you are inside the drive box its best to replace the control potentiometer and microswitches with good quality new ones. Also change the spring on the the selector arm. They do get tired. £40 – £50 on spec is worth it just to know you'll not get trouble there again in this decade. Connections can get iffy too over the years.



Generally the Erskine is a very durable unit but age eventually gets to them. Fortunately they are old school discrete components so repair is practical. Probably around £150 – £200 from folk who specialise in such work.



Clive

Edited By Clive Foster on 24/01/2018 12:08:02

Edited By Clive Foster on 24/01/2018 12:08:47

[David Leahy 1Participant @davidleahy1]

I have checked out the red reset button. I push it down but it does not stay down, ie it does not clip and stay down? I assume it should?

[Clive FosterParticipant @clivefoster55965]

Yup overload reset button should latch and stay. Can you do an album and upload a picture or two of your contactor so we can see what type you have.

Lot of different types out there.

Failure to latch and / or random operation is a known, albeit usually reasonably rare, issue with several varieties of overload units when they start getting old. Some can be fixed but some can't either due to breaking inside or being impossible to get into and reassemble. Some broken ones can be replaced with a modern overload unit retaining the existing contractor but sometimes you just have to get a new contractor and overload.

Mine just needed a couple or three good blasts of switch cleaner and a few manual on – off cycles.

Clive.

[EmgeeParticipant @emgee]

David, if there is no click heard when pressing the red button I think the overload has not tripped so the control cct will not be broken by the overload device. Best isolate power and check through the control cct with a meter.

Emgee

[David Leahy 1Participant @davidleahy1]

That's good advise, I assume the red thermal overload button has some sort of bi-metallic assembly within it that releases the contact in response to increased heat. Yes I agree given it doesn't click when pressed, there is no sign of charring that the contact just has not popped.

I will send across images of the contactors if this is any help as advised by Clive.

I will order up a new cap to replace the burnt one and see how it functions from there.

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