View Full Version : Identify components in Bridgeport electrical box

02-20-2013, 09:35 AM
The attached pics show the electrical box that was attached to my new-to-me Bridgeport.

I was originally just going to detach it and set it aside as-is for some potential future 3-phase usage.

Now I think I may "re-task" it for my 1-phase VFD implementation, rather than buy new electrical hardware.

I'm employing new start/stop buttons, speed pot, direction switch, & possibly a jog button, all of which will, of course, be connected directly to the low-voltage terminal strip on the VFD.

I'll keep the contactors and fuse assemblies intact, and possibly the 2:1 transformer for driving the lamp, but the other hardware, appears to be "interlocks" for the original start/stop buttons, in which case, they would not be needed. The space could be used for the VFD.

Can someone please identify these components in the bottom end of the box?


http://i1356.photobucket.com/albums/q730/jmarkwolf/Bridgeport_Electrical_Box6_Annotated_zpse3b1b55b.j pg


02-20-2013, 09:45 AM
The item in the large circle is a magnetic motor starter. It is equipped with overload protection. That is what the white semi-circular buttons are for, to reset the overload kick outs when tripped.

You won't need that for your VFD installation. I'm sure the existing start/stop control switches can probably be reused though. Most VFD's can be setup to use common control schemes. Your's is more than likely a 3 wire start/stop. Very common setup. Just guessing about the wiring though.


02-20-2013, 11:05 AM
Top to bottom; knife blade switch, fuses, heater(overload protection), magnetic contactor.
I would keep the knife blade switch, fuses, lamp driver(?) and remove the rest, placing the VFD below the fuses. Your VFD should cover it from there. My forward reverse 'drum' switch I rewired using the appropriate terminals on the VFD. VFD's need some ventalation, check the manual as your box looks gasketed (air-tight).

02-20-2013, 11:26 AM
Most VFD manuals recommend a contactor on the input supply, this is dropped out by E-stop, you could use the contactor for main E-stop contactor, remove or bypass the O/L's and fit fusing on the respective other loads.
The transformer is rated for 600ma so a bit light for general 120v supply and control.

xs hedspace
02-20-2013, 01:34 PM
Just go from the bottom fuse connections, to the VFD. The ON/OFF switch is good to have, if smoke starts coming out of your VFD. The transformer if it goes to the light, keep that in the circuit. Otherwise, all the controls should come with the vfd. Disconnect the contactor/relay part.