Motors
3-Pase power
Calculations
Name that movie from the fictional place.
100
Motor Info - single, continuous duty 15HP, 480V, 3ph motor with 21FLA
What is the recommended quantity and size of the phase conductors?
#10AWG (NEC 430.22)
100
In a 208V, 3 phase circuit, what is the phase-to-phase voltage?
208V
100
What size breaker should the main of a 480V, 3ph, 1250kW, .8pf generator be?
2000A
100
Hoth
Star Wars The Empire Strikes Back
200
Motor Info - single, continuous duty 15HP, 480V, 3ph motor with 21FLA
What table do I used to size the ground wire for the motor feeder?
Table 250.122 (NEC 250.122(D))
200
In a 3-phase, 4w system what should the ideal neutral-to-ground voltage be?
0V
200
What size breaker should supply a 480V, 3ph AHU/RTU with (6) 10HP motors (14FLA/mtr)?
100A
200
Raccoon City
Resident Evil
300
Motor Info - single, continuous duty 15HP, 480V, 3ph motor with 21FLA
What is the recommended over current protection size?
40A/3P
300
In a 480V, 3 phase, 4w circuit, what is the phase-to-neutral voltage?
277V
300
A 100A feeder needs to be upsized from a #3 to a #1for voltage drop. What size should the ground wire be upsized to?
#4
300
Arrakis
Dune
400
Motor Info - single, continuous duty 15HP, 480V, 3ph motor with 21FLA
What is the largest breaker size that can be used per code?
60A/3P
400
How many conductors should there be in a 3 phase, 4 wire, circuit? Name them all
5 (3 phase, 1 neutral, 1 ground)
400
What ampacity should the supply for a 480V, 3ph AHU/RTU with (4) 15HP motors (21FLA/mtr) and 50kW of electric heat?
(Bonus points for wire and conduit sizes)
150A (wire size – 3#1/0,#6G,2”C)
400
Duloc
Shrek
500
Motor Info - single, continuous duty 15HP, 480V, 3ph motor with 21FLA
If the largest breaker size is to be used, what size should the phase conductors be? Bonus points for the ground wire size.
#10 AWG (motor feeder conductor sizes are not based off the breaker size.)
#10G AWG (NEC 250.122(A) – “…The equipment grounding conductor shall not be required to be larger than the circuit conductor suppliying the equipment.”…
500
In a 208Y, 3ph, 4w circuit with 10A on each phase conductor, how many amps should be on the neutral conductor?
0 (this is why we do not pull neutral conductors to balanced 3-phase circuits like dedicated motors.)
500
What size breaker should be given to a 208V, single phase electric water heater with (2) non-simultaneous 10kW heating elements?
60A
500
Hill Valley, California
Back to The Future Trilogy