Question for the more knowlable

the tractor vet · Feb 1, 2011

Electricians out there . How many watts will a 1/2 hp furnace motor require?????? Just in case i have to barnyard engineer a makeshift set up if we loose power.

IaGary · Feb 1, 2011

A 1/2 hp will be about 7 amps so 7 amps times 110 volts would be 770 watts.

Give or take a few.

If it is on 220 it will draw 3.5 amps times 220 or about the same.

Gary

TimV · Feb 1, 2011

Tractor Vet: two other things to consider--starting current required can be 2x or even more of what the running current is, and many newer furnaces are electronically controlled and the electronics may not like being fed dirty power from a generator. I know several people who tried to run their furnace off from a generator and were unable to get it to fire up because of this. Just some things to keep in mind and possibly check out BEFORE you're in an emergency no-heat situation.

the tractor vet · Feb 1, 2011

Nah it is and OLD one just like me. It was installed in the summer of 68 so no electronics , just a electric gas valve and blower motor

the tractor vet · Feb 1, 2011

Just 110 , so i should be sorta good to go then. If the power does go down i can tap in at the furnace fuse switch and shut the main breaker to it at the breaker box and unhook the wire and bug it in .Thanks i may know my farmall's but never claimed to be and electrician .

smallercrawler · Feb 1, 2011

TTV, 1HP (electric) is 746 watts, therefore 1/2 HP is 373 watts. At 120 volts this is about 3.1 amps, at 240 volts it is about 1.55 amps. These are RUNNING currents, STARTING will be greater.

supergrumpy · Feb 1, 2011

neighbor taught me this:

if you have "fan" position on your thermostat turn the fan on first and let the generator settle down after the surge

then start the furnace, furnace doesn't take much juice but the blower does

Bob · Feb 1, 2011

That's THEORY, with a 100% efficient motor.

In the REAL world, 1.5 to two times what you posted.

Janicholson · Feb 1, 2011

Good advive here. T.V. what are you using for the power source? Jim

Roger in Iowa · Feb 1, 2011

My 3500 watt generator barks when the fan is turned on, and I leave it on. Then turn furnace on plus refrigerator and a couple of lights.

DaveK(IN) · Feb 1, 2011

Another safe way to prepare for this is to install a receptacle on the end of the furnace branch circuit and a cord and plug to connect the furnace. Plug it in and it runs normally, just unplug it when you need to power it from a generator and extension cord. This avoids all the problems and potential dangers of back feeding your house distribution system.

smallercrawler · Feb 1, 2011

Bob, you are CORRECT-I was having trouble with post and forgot to add that assumes 100% efficiency and a unity power factor. Two online calculators show 5.8A/2.9A for 120/240 volts. THANKS!

Anonymous-0 · Feb 1, 2011

Hello, I have a very early serial number model G John Deere. Serial number 3963. I need all four valves. Can anyone help me? All I can find is valves for seriall 13000 and up. My email is [email protected] Any help will be greatly appricialted.

bill b va · Feb 1, 2011

look on the data plate on the motor . it will tell the running amps.. starting amps will be 2-3 times higher for a few seconds. all ac motors have this plate .( that i have seen )

Question for the more knowlable

the tractor vet

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IaGary

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TimV

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the tractor vet

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the tractor vet

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smallercrawler

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supergrumpy

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Bob

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Janicholson

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Roger in Iowa

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DaveK(IN)

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smallercrawler

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Anonymous-0

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bill b va

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