Converting to DC blower motor [RE-wrenches]

[Windy Dankoff, Dankoff Solar]

<x-flowed>Roy said:

>... I have a large wood furnace which heats my
>workshop, office and showroom. A built-in thermostat controls 2- 1/7
>horsepower AC blowers which produce a combined air flow of 1300 CFM.
>Between these 2 power hogs, 360 watt-hours of electrons are murdered. I
>have wanted to switch to a single 24 VDC motor for some time now but one
>thing stops me....what do I do about that thermostat? It's rated for AC
>only and I'm aware of what's supposed to happen to AC contactors when used
>with DC.

If your AC thermostat is in the primary (power) circuit to the motor, 
and it uses an ordinary moving-contact mechanical switch mechanism, 
then you can probably use it with no problem.

Apply this rule that I have followed succesfully since pre-inverter days:

Amps rating at 125VAC = Amps rating at 24VDC or less.

At 48V, amps rating would be half.

In other words, the arc of DC is thought to be of greater intensity 
than than of AC, but only at equal voltage. At the lower voltage, 
it's about equal.

If you aren't sure about your particular thermostat, consult your 
Grainger catalog for "line voltage thermostats" (rated for some amps 
at 125VAC) or for their little snap disc thermostats. Some of these 
devices have DC ratings, which will confirm for you the relationship 
that I have stated above.


>And....any recommendations for a good (read affordable!) DC double
>shaft motor? Doesn't have to be double shaft....quite likely I'll stick to
>my original plan and convert this to a single motor/blower.
>     Anyway....I'm open to any and all suggestions!

Surplus Center catalog and C & H Sales catalog have various DC 
motors. Also, I am happy to supply any of the motors that we use on 
our DC pumps. Ours are too big for your blow, but we've used them for 
countless other applications -- fans, blowers, belt-driven machinery 
of all kinds, and ....

Windy


-- 

	===========================

	From the solar powered office of
	     Windy Dankoff, President

	===========================

Dankoff Solar Products, Inc.

    Wholesale distributor of solar-electric equipment
    Manufacturer & distributor of solar water pumps

2810 Industrial Rd.
Santa Fe, NM  87505

(505) 473-3800
FAX  473-3830
E-mail:	  info at dankoffsolar.com

SEE OUR INFORMATIVE WEB SITE AT:

http://www.dankoffsolar.com

	===========================

	To contact Windy Dankoff directly:
	Most days I am at my home office
	e-mail:  windy at dankoffsolar.com
	   tel/fax:  (505) 466-0059
	   ~ amateur radio KE5HV ~

	===========================

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