eric_hoog
Member
- Location
- Ottawa, ON, Canada
I relaize this is probably very basic to most of you as I am a student doing a self study using Delmar's Standard Textbook of Electricity. But I just wanted to verify my answer to one of the practical questions I have came across. Any information, help, or tips would be greatly appreciated.
Well here it is:
#2 ? You are an electrician installing the wiring in a new home. The homeowner desires that a ceiling fan with light kits be installed in five different rooms. Each fan contains a light kit that can accommodate four 60-watt lamps. Each fan motor draws a current of 1.8 amperes when operated on high speed. It is assumed that each fan can operate more than three hours at a time and therefore must be considered a continuous-duty device. The fans are to be connected to a 15-ampere circuit. Because the devices are continuous duty, the circuit current must be limited to 80% of the continuous connected load. How many fans can be connected to a single 15-ampere circuit? How many circuits will be required to supply power to all five fans?
15 A * 0.8 = 12 A (80% of 15 A is 12 A so that is the max current allowed per circuit)
Each fan draws:
4*60W = 240 W (power used for lights on each fan)
On a 240 V circuit the lights would draw 1 ampere of current (I =P/E). With the motor the total current draw for each unit would be 2.8 A. So 12 A / 2.8 A = 4.2 units per circuit. So there could be 4 fan units on each circuit and would need 2 circuits.
On a 120 V circuit the lights would draw 2 amperes of current (I =P/E). With the motor the total current draw for each unit would be 3.8 A. So 12 A / 3.8 A = 3.15 units per circuit. So there could be 3 fan units on each circuit and would need 2 circuits.
I would assume that they would be using the 120 V circuit for this application but I included both voltages to cover everything. Does this sound correct you?
Also, I am very interested in pursuing a carreer in the electrical feild here in Canada. Other than going to school and getting a diploma (which I plan on doing) are there any suggestions, tips or information resources you can tell me about that would help me to facilitate my goal? If so please let me know it would be greatly appreciated. I'm currently studying Delmar's Standard Textbook of Electricity as I believe this is a great starting point.
Anyways, thank you a head of time for any help you can give me!
-Eric
Well here it is:
#2 ? You are an electrician installing the wiring in a new home. The homeowner desires that a ceiling fan with light kits be installed in five different rooms. Each fan contains a light kit that can accommodate four 60-watt lamps. Each fan motor draws a current of 1.8 amperes when operated on high speed. It is assumed that each fan can operate more than three hours at a time and therefore must be considered a continuous-duty device. The fans are to be connected to a 15-ampere circuit. Because the devices are continuous duty, the circuit current must be limited to 80% of the continuous connected load. How many fans can be connected to a single 15-ampere circuit? How many circuits will be required to supply power to all five fans?
15 A * 0.8 = 12 A (80% of 15 A is 12 A so that is the max current allowed per circuit)
Each fan draws:
4*60W = 240 W (power used for lights on each fan)
On a 240 V circuit the lights would draw 1 ampere of current (I =P/E). With the motor the total current draw for each unit would be 2.8 A. So 12 A / 2.8 A = 4.2 units per circuit. So there could be 4 fan units on each circuit and would need 2 circuits.
On a 120 V circuit the lights would draw 2 amperes of current (I =P/E). With the motor the total current draw for each unit would be 3.8 A. So 12 A / 3.8 A = 3.15 units per circuit. So there could be 3 fan units on each circuit and would need 2 circuits.
I would assume that they would be using the 120 V circuit for this application but I included both voltages to cover everything. Does this sound correct you?
Also, I am very interested in pursuing a carreer in the electrical feild here in Canada. Other than going to school and getting a diploma (which I plan on doing) are there any suggestions, tips or information resources you can tell me about that would help me to facilitate my goal? If so please let me know it would be greatly appreciated. I'm currently studying Delmar's Standard Textbook of Electricity as I believe this is a great starting point.
Anyways, thank you a head of time for any help you can give me!
-Eric