Shopbot PRS 48x96 Acorn / Clearpath Conversion

[paulwall]

Question - Is it poor practice to 'double tap' a single breaker with two different PSUs?

[paulwall]

Progress is slow but steady. I've got the basic placement for most of the larger components done.

One of the more formidable things I haven't done is research what AWG belongs where, so that'll be this weeks reading.

[cncsnw]

It is not unreasonable to use a single circuit breaker for multiple loads.

If there were more than two loads, I would run the power to terminal blocks, rather than putting more than two wires on the load side of the circuit breaker.

To be strictly proper, the wiring from the breaker to each load needs to be sized for the breaker, rather than for the load. E.g. if you use a single 10A breaker to supply two 5A loads, then you need to use 16ga wire from the breaker to each load. If you used two separate 5A breakers, then 20ga wire would be sufficient for each.

There are exceptions, at least in NFPA79, that allow control circuit conductors (not motor power conductors) to be considered "protected" by circuit breakers in excess of the normal wire ampacity, particularly if those conductors do not leave the cabinet.

Did your "PSU" question relate to motor power supplies, or to logic power supplies?

[paulwall]

I had not put two and two together before! - 'size wire to the breaker, not to the load' Thank you for that and all the other information.

I'll only be double tapping (or rather using terminals to distribute) two low current PSUs for my mini PC and PC monitor, both of which are under 2A each max draw. All the other primary devices will be on their own breaker.

[paulwall]

I am back at the build. Had a bit of a busy summer with work, but the machine frame is up and the gantry level... the gantry only took a few days of cursing to get that way.

I do have a part I can't seem to locate if anyone can help - Does anyone have a source for the follow spur gears? I can only seem to find 3/8" face width gears with matching pitch and pressure angle specs.

Face width - 0.50"
# of Teeth - 25
Pitch - 20
PA - 14-1/2°

[Gary Campbell]

It may be tough to find gears for 14 1/2 pressure angle. They are not designed for the torque and speed of cnc routing. SB had them years ago on the PR models and had to upgrade. IF you do find them, I would suggest buying extras, they wont last long.

[tblough]

Http://rushgears.com

[paulwall]

Thanks guys. It looks like a custom gear may be my only option, that or running 3/8" face spurs on the 1/2" width racks my machine has.

I may reach out to RushGears for a quote, but I'm expecting that to be an arm and a leg.

[tblough]

You could also search for pinion stock. http://shop.sdp-si.com/catalog/product/ ... C29-N20020 sadly it's out of stock.

[paulwall]

I couldn't quite find what I was looking for on SDP/SI, though their stocks might be an option, but machining them down is looking to be pricey.

I submitted a few custom gears through RushGear's RFQ system - We shall see what kind of damage they pose to the budget.