Search found 1645 matches

by John Hasler
Tue Jan 19, 2021 8:43 pm
Forum: Riding Scale Railroading
Topic: Controlling separate DC traction motors
Replies: 5
Views: 165

Re: Controlling separate DC traction motors

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...
by John Hasler
Tue Jan 19, 2021 4:36 pm
Forum: General Discussion
Topic: Why do I need a Variac?
Replies: 7
Views: 119

Re: Why do I need a Variac?

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.
by John Hasler
Tue Jan 12, 2021 9:22 am
Forum: Riding Scale Railroading
Topic: Electric power primer
Replies: 27
Views: 4492

Re: Electric power primer

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 ...
by John Hasler
Sun Jan 10, 2021 9:04 am
Forum: Live Steam
Topic: Could I get tips on dumpster diving for materials for your build?
Replies: 52
Views: 2856

Re: Could I get tips on dumpster diving for materials for your build?

I think that if you must interference fit aluminum onto steel you need to shrink it on, not press it.
by John Hasler
Fri Jan 08, 2021 11:10 am
Forum: Live Steam
Topic: Could I get tips on dumpster diving for materials for your build?
Replies: 52
Views: 2856

Re: Could I get tips on dumpster diving for materials for your build?

>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.
by John Hasler
Thu Jan 07, 2021 9:49 pm
Forum: Live Steam
Topic: Could I get tips on dumpster diving for materials for your build?
Replies: 52
Views: 2856

Re: Could I get tips on dumpster diving for materials for your build?

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/
by John Hasler
Thu Jan 07, 2021 11:09 am
Forum: Live Steam
Topic: Could I get tips on dumpster diving for materials for your build?
Replies: 52
Views: 2856

Re: Could I get tips on dumpster diving for materials for your build?

>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.
by John Hasler
Thu Jan 07, 2021 9:26 am
Forum: Live Steam
Topic: Could I get tips on dumpster diving for materials for your build?
Replies: 52
Views: 2856

Re: Could I get tips on dumpster diving for materials for your build?

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.
by John Hasler
Wed Jan 06, 2021 11:30 pm
Forum: General Discussion
Topic: Compressor timer switch question
Replies: 35
Views: 1125

Re: Compressor timer switch question

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.
by John Hasler
Wed Jan 06, 2021 12:41 pm
Forum: General Discussion
Topic: Compressor timer switch question
Replies: 35
Views: 1125

Re: Compressor timer switch question

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 ...
by John Hasler
Wed Jan 06, 2021 12:02 am
Forum: General Discussion
Topic: Compressor timer switch question
Replies: 35
Views: 1125

Re: Compressor timer switch question

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...
by John Hasler
Tue Jan 05, 2021 7:35 pm
Forum: General Discussion
Topic: Compressor timer switch question
Replies: 35
Views: 1125

Re: Compressor timer switch question

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...