circuit breakerelectric motorelectricalfanhvac
This fan lists its "Max. Amperage" as 3.2. I assume the motor draws that much when it's first turning on, then settles down to some lower current. How much current should I expect it to draw when it's running steadily?
I ask because I want to know how a) how much this will cost me to run for a month continuously, and b) how much it will heat the space. I'm figuring that all the energy the motor draws gets swiftly converted into heat. Please correct me if I am thinking about this incorrectly.
Somewhere inside the service panel of the furnace, there should be a schematic for the furnace. This may list the electrical specifications of the blower motor. If not, the blower motor itself will have a label on it. It should list the voltage, amperage, horsepower, etc.
An ammeter is used to measure the amount of current flowing through an electrical circuit. You can use a clamp on ammeter to measure the amount of current being used by the blower motor while it's running.
Simply set the meter to measure current (A in the pictured meter), and clamp it on the hot wire feeding the motor.
This method may require working on or near live wires, please use caution and/or consult an expert to take the readings
With the above information and Ohm's law, it's easy to determine how much power the motor will use over a given time period.
Ohm's law says that Power (P) = Voltage (V) x Current (I), so we can determine how much power the motor uses at a single instant in time.
ex.
P = 115V * 5.2A
P = 598 Watts
Next we have to determine how many kilowatt hours the motor will use, which we do by dividing by 1000.
P = 598 W / 1000
P = 0.598 kWh
So for every hour the motor runs, it will use 0.943 kilowatts of power.
Total power/day = 0.598kWh * 24h
Total power/day = 14.352kWh
Total power/month = 14.352Kwh * 30
Total power/month = 430.56kWh
Finally, if you multiply this number by the amount you pay per kilowatt hour. You'll see just about how much it costs to run the motor constantly.
Cost = 430.56kWh * $0.07
Cost = $30.14 per month
Notes:
Results using this process will be an estimate only.
Values used are not actual values, they are example values only.
Calculations may be incorrect, nobody checked my math.
It appears according to the manual for the Mastertrol Automatic Balancing System (MABS) EZ Zone (EZ-2 and EZ-4) Control Panels (PDF), that M1 is used for C.
Click for larger view
This does not appear to be the manual for your device, so this information may not be correct.
The manual for the MABS 2 Zone Panel (PDF), also shows M1 being used for C.
After further review, you should be able to connect the C wire directly to the transformer terminals. Measure for Voltage between the T5 terminal of the zone you're working in, and the 1 and 2 terminals in the 24V 40VA Transformer section. One should measure 24 Volts, while the other measures 0 Volts. The one that gives you 24 Volts, should be able to be used as C.
Best Answer
You can't determine the actual amperage from the maximum. If the manufacturer did not provide this information (which is usual) your best bet is to use a device like a Kill-A-Watt (disclosure: I have no affiliation with this product nor have I ever used it, the name just stuck in my head). This device plugs into the wall and you plug the appliance into the device. It measures the amperage that the appliance draws.