Search found 1825 matches

by John Hasler
Fri Sep 03, 2021 8:32 pm
Forum: General Discussion
Topic: DC variable speed motors
Replies: 15
Views: 6953

Re: DC variable speed motors

Probably not the manufacturer's nameplate.
by John Hasler
Thu Sep 02, 2021 9:15 am
Forum: General Discussion
Topic: DC variable speed motors
Replies: 15
Views: 6953

Re: DC variable speed motors

BigDumbDinosaur wrote: Wed Sep 01, 2021 11:56 pm This motor is an intermittent-duty unit.

Also, if you carefully read the nameplate in the one photo it says "60 Cycles". I must say I've not run into too many DC motors that run on 60 cycles. :D
May be a series wound "universal" motor.
by John Hasler
Thu Sep 02, 2021 7:26 am
Forum: Casting & Foundry Work
Topic: Oil fired crucible furnace
Replies: 15
Views: 17475

Re: Oil fired crucible furnace

>One thing you should know is that the nozzle will be at the end of the necked down tube, so there shouldn't be any combustion behind the nozzle. I'm assuming, perhaps incorrectly, that the mixture of air and atomized oil enters the fat end of the tapered tube. If so you have a blowback hazard becau...
by John Hasler
Wed Sep 01, 2021 6:03 pm
Forum: General Discussion
Topic: DC variable speed motors
Replies: 15
Views: 6953

Re: DC variable speed motors

Treadmill motor. Good for 3/4 hp for perhaps five minutes out of each hour. Ok motors when you can get them cheap or free but you have to derate them. The controller looks like junk. The package is over priced.
by John Hasler
Wed Sep 01, 2021 4:07 pm
Forum: Casting & Foundry Work
Topic: Oil fired crucible furnace
Replies: 15
Views: 17475

Re: Oil fired crucible furnace

Other things being equal dropping the nozzle diameter from 4" to 1.5" will give you 7 times the nozzle velocity. The flame wants to burn at the point where the flow velocity equals the flame front velocity (a constant, more or less). If you don't reduce flow the flame may lift or blow out....
by John Hasler
Tue Aug 31, 2021 6:05 pm
Forum: Riding Scale Railroading
Topic: clearance height for batteries
Replies: 8
Views: 6450

Re: clearance height for batteries

With lithiums don't rely on "should be sufficient". Do the calculation.
by John Hasler
Tue Aug 31, 2021 6:02 pm
Forum: General Discussion
Topic: Help reading print please
Replies: 8
Views: 4583

Re: Help reading print please

They are telling you that the hatched area shows a cross-section.
by John Hasler
Tue Aug 31, 2021 11:57 am
Forum: Live Steam
Topic: ORC, Freon instead of Water
Replies: 11
Views: 5234

Re: ORC, Freon instead of Water

>The fire side resistance R1 may be 100 to 500 times the resistance of the metal wall R2, and the fluid side resistance R3 may be 10 to 50 times the resistance of the boiler wall. Engineeringtoolbox has tables, equations, and calculators to help compute the heat transfer from the hot gas to the tube...
by John Hasler
Mon Aug 30, 2021 12:21 pm
Forum: Riding Scale Railroading
Topic: clearance height for batteries
Replies: 8
Views: 6450

Re: clearance height for batteries

>Should have asked, Would this matter if I latter converted to lithium? (Possible future plan.)

Yes. With lithium cooling is a major consideration.
by John Hasler
Mon Aug 30, 2021 10:04 am
Forum: Live Steam
Topic: ORC, Freon instead of Water
Replies: 11
Views: 5234

Re: ORC, Freon instead of Water

Googling

thermodynamic properties of R365mfc

gets los of hits.
by John Hasler
Mon Aug 30, 2021 8:00 am
Forum: Riding Scale Railroading
Topic: clearance height for batteries
Replies: 8
Views: 6450

Re: clearance height for batteries

Two inches will be adequate. With only four batteries just make sure that there *is* ventilation and you'll be ok. Hydrogen only comes off during charging. I did the electronics for a medical standby power unit that had four turck batteries in a stainless steel box. The project engineer was concerne...
by John Hasler
Wed Aug 25, 2021 3:06 pm
Forum: Riding Scale Railroading
Topic: Remote Control thoughts
Replies: 43
Views: 32855

Re: Remote Control thoughts

2.4 GHz is an ISM band available for WiFi on a non-interfering basis. Not a good idea to use it for anything that really matters.