On 2008-05-22, DoN. Nichols wrote:
On 2008-05-22, Ignoramus12247 wrote:
On 2008-05-22, Pete C. wrote:
It's a Bridgeport mill. No drum switch will remain and there will be no
speed pot. I'm quite comfortable with entering the speed and run stop
using the VFDs keypad. Rather similar to the Sxxxx M03 deal on a CNC.

BP drum switch is kind of hard to rewire.

Why? -- The internal wiring of the drum switch is as follows:

LINE MOTOR
o----------+-----------o (L1)
L1) o--------o-------- |
o-------+ |
| /|\
o-------+- | ----------o (L2)
L2) o--------o-------- |
o----------+

o--------+
L3 o--------o-------- |
o--------+-------------o (L3)


And all you need to do is connect the one which I have marked
(L1-LINE) to the common on the VFD, and (L1-motor) to FWD, and
(L2-motor) to REV. Totally ignore all the rest of the terminals on the
switch. If you can't figure out which is which, use a multimeter to
find a terminal on the switch which is connected to another terminal
only in the FWD position and to a third terminal in the REV position.

I looked at that. What I found difficult was not the schematic, but
that there are barely enough wire length coming out of the motor, to
reach the drum terminals. I think not even enough to make wire nut
connections. Schematic wise, you are 100% on target.

I also find the placement of the drum switch, to be not perfectly
convenient, at least for me.

So the only time when I reach for and switch it, is when changing from
direct to back gear.

i