H1 H2 H3 wires for space heaters (Induction motor) 1

[RM12]

I have 4 space heaters in a motor rated for 240V 1000W each. The aux box has three wires H1 H2 and H3. Can anyone explain how the wiring would be for the heaters with the three wires. How are they connected to operate these heaters either using 120V or 240V?

 

[waross]

I can make a wild guess what voltages are represented by H1, H2, H3, but I'd rather not.
What you call space heaters are most likely anti-condensation heaters.
Normal practice and recommended practice is to run anti-condensation heaters at half rated voltage.
Most common is 240 Volt rated heaters supplied with 120 Volts. It doesn't take much heat and the heaters lasr forever.

 

[edison123]

 

[waross]

Are you suggesting two, 240 Volt, 1000 Watt heaters in series across 120 Volts?
60 Volts per 240 Volt heater?
62.5 Watts per heater?
I would rather see 120 Volts per 240 Volt heater for 250 Watts per heater.

 

[TugboatEng]

It wouldn't make sense to bring a single H3 wire back to the junction box if the heaters were connected in series. If you have 240v single phase, connecting H1-L1, H2-L2, and H3-N places the heaters in parallel with 120V across each heater.

You should be able to verify that these heaters are wired in this configuration using your ohmmeter.

 

[edison123]

OP said 4 x 240 V x 1000 W heaters with 3 terminals suitable either for 240 V or 120 V. If there is another connection possible for both 240 V and 120 V, please post here.

Yes, 62.5 W for each heater and 250 W in total. Which is what I find in large motors. It's enough to keep the motor warm.

 

[edison123]

Now you get 1000 W in total.