The Home Machinist!

These motors are likely to match much more closely than your RC motors, especially if the RC motors were PM. It's still a concern, though. You could sometimes have one axle slip and the other not. The ideal arrangement would be to install a tach on each axle and have a microcomputer manage the motor...

Triac chopper speed controls are not useful for testing inductive loads such as AC relay coils or for determining the correct AC operating voltage for a device unless it is purely resistive and you have a true RMS voltmeter.

There is a schematic in the manual (http://www.fsip.biz/Documents/1204_05.pdf). You probably cannot use a single pot for two of those controllers. Check with Curtis. Each motor requires four sets of contacts for reversing. The schematic in fig. 6 in the manual is good. Maximum total current will be ...

I think that if you must interference fit aluminum onto steel you need to shrink it on, not press it.

>The only problem is that cost of shipping often exceeds value of the product...

Still cheaper than Menard's, though.

> Forget brass.

When I cleaned out my father's shop I gave away several hundred pounds of brass because I didn't want to haul it down here. A mistake I regret.

There are also online metal suppliers. I've had good luck with Speedy Metals. If you are in the upper midwest place your order by phone and ask that they ship via Spee-Dee Delivery. Faster and cheaper than UPS.

https://www.speedymetals.com/

https://speedeedelivery.com/

>That being said: there are some parts where you are definitely better off using material of a known specification and quantity...

Yes, of course. I don't build locomotives, but I do buy new material when necessary.

I don't take "dumpster diving" literally. Getting drops for free counts as "dumpster diving" in this context.

I really don't understand the hostility to the idea of repurposing junk and scrap in order to save money.

A starter has overload protection ("heaters"). He doesn't need that as his motor has internal thermal protection. He just needs a contactor rated for 5 hp.

The motor is "compressor-rated" at 5 hp. This seems to mean that it can deliver the same starting torque as a NEMA 5 hp motor and can deliver 5 hp for the last few seconds just before the pressure switch shuts it off without tripping the thermal overload. This rating assumes intermittent duty and a ...

Circuit breakers don't trip instantly when their rated current is exceeded. They integrate (a function of) the current over time. The startup current for that motor is certainly more than 20 amp. Compressor motors need to deliver high starting torque which means high starting current. What is the co...

Bill is right. The device that actually switches the power to the motor must be labeled for the motor hp (which is not quite the same thing as being rated for the motor starting current). Cycling the power makes no difference to the pressure switch: it's purely mechanical and cares only about pressu...