Bridgeport electrics

Have just aquired a bridgeport which has been used with an inverter to drive the head. The previous owner did not use the table feeds so I want to get it all up and running. I would normally wire the motor back to original but the table feed motors have a voltage rating, part of which I can't read and I don't undrstand the part I can read. It says ?0A/100F. The part where I have put ? is hidden by the "s" in volts. It might be 90A. Can somebody explain what this means please?

Thanks

Hi Nick,
I think you will find the feed motors are powerd (Via the speed control circuitry) from 110 v AC supply from a transformer. The primary of this transformer is about 400 v which is connected between two phases. I have seen at least three different wireing diagrams so you will have to trace the wireing on your machine. I think there may be a 230 V tap on the primary so you could power it from normal mains.

Les.

Hi Nick

Les is quite right I have a machine which has power feed on either the X or Y feed, not both together you should have a large transformer which supplies 110 volt for the power feed electronics and also a low volts feed for the machine light, this can be either 12 Volts or 24 Volts or 50 Volts. when I got my machine the power feeds were not working. this turned out to be two faults one in the electronic speed control unit ( mine is a long black box at the bottom of the power cabinet and the other was one of the speed setting pots on the motor unit its self. I would not worry about the markings on the motors. On my machine this transformer also feeds the coolant pump.

regards

David

Which power feed, there are at least 3 types ?

Thanks everybody. Does this mean I can just plug my machine into a converter and could I use an inverter if I wanted? I suppose I could use an invertor and run the feed motors of mains through the transformer if there is a suitable tapping? Is thiscorrect?

The 6F type on my machine run off the inbuilt Bridgeport transformer, it does indeed have a 230v tap.

Regards

Paul

Hi Nick,
I do not understand the questions in your post at 21:28 You need to specify exactly what you mean by "converter" If you mean say a 20 HP single phase motor driving a 20 HP three phase alternator the answer would be yes but I do not think this is what you mean. Why would you want to use an inverter to generate three phases and then only use one of these phases to drive the transformer ? If the feed motors are supplied from the 110 v output of the transformer then all you need to do is use the 230 v primary tapping and feed it with normal 230 v single phase mains. If the tap is not present then buy a suitably rated 110 volt transformer.

Les.

Hi Les

I have a converter and a couple of inverters. I have another milling machine which I run off the converter and all I did with that was plug the main feed cable into the converter. This then runs the main motor, feed motor and coolant pump without any alteration to the existing electrics. With the feed motors on the Bridgeport being a different voltage I wasn't sure if I could do the same, bearing in mind the converter only uses two phases and fools the motor on the third phase (as I understand it) . I didn't know if this would work the transformer.

I am only trying to gain relevant knowledge at the moment and I do understand I have various options that I can use.

Many thanks for all the replies

Nick

Hi Nick,
It sounds like your "converter" is the type that just uses capacitors to provide phase shift. The value of the capacitors depends on the size of motor it is driving. If the power rating of the Bridgeport motors is about the same as your other mill then you should be OK running the Bridgeport's three phase motors from it. I would still suggest providing the 110 v supply for the feed motors via a transformer from normal mains. One of the output phases of this type of converter is normaly connected directly to the incomming single phase. If you post a schematic of the converter myself or many others on the forum will be able to confirm this.

Les.

Hi Nick

The Power feeds I have fitted are the Bridgeport 6F type to help you identify the motors fitted on my machine are as follows

Motor "Fracmo" made by "Factional HP motors Ltd Enfield England

Frame No H39412TBX

Volts 90A 100F

Phase DC

Amps 4.6

RPM 4500

HP 370 Watts

Rating INT (intermitent)

On the front panel is a "Feed Rate" control and a "Rapid Traverse" Switch

Please note the motors are DC not AC and must be driven by an electronic speed control unit, This is normaly in the bottom of the electric's Cabinet

Does this fit with what you have ?

Regards

David

Hi Nick

I meant to say that this is a compleatly seperate issue to how you supply the 440 Volt three phase supply to the machine.

Regards

David

Hi Nick

Do you have a manual ? if not then the best one I have found can be found via the following convoluted path

1 go to www.bridgeport.askmisterscience.com

2 scroll down to Bridgeport literature and manuals

3 select Bridgeport M105H series manual PDF 26.4 mb

4 which should down load from a site www.bbssystem.com

for some reason you cannot go straight to this site

regards

David

On the subject of Bridgeport manuals this one may be of interest.

Les.

Hi David

Thanks for your reply. Yes my feed motors are the same as yours. I think if I run the main motor from the inverter and the feed motors through the inbuilt transformer using the 240v input on the primary it should run through the normal system and give me a dc supply to the feed motors. The only problem I can see with this is that the feed motors won't run without the main motor switched on through the normal switch. Alternative is to run an inverter ino the normal wiring and alter the main motor voltage from 440v to 250v and also the transformer input to 250v. Havn't thought too much about this yet but I think it should work.

Nick

Hi Nick

You are correct in saying the feed won't run with out the main motor running, this is a safety feature I would not bypass this, as it is easy to forget the table is still moving on a very slow feed.

Do you have the origonal feed motor speed control module, if so there is a wireing diagram in the manual.

Regards

David