dubba said:In my area most of the savings from using 3 phase on larger motors is because of the way the electric company bills business accounts.
We pay for usage & peak demand. By using 3 phase equipment the usage stays approx the same but the demand per input is lower. The current combined demand charge in my area is $6.88 per highest average KW demand.
So from tommu56's example on a motor run for 1 hour continuously-
one horse motor 120v 16.amps = $13.21 demand charge
same on 3 phase 7.2 amps = $5.94
BillyP said:I don't know a thing about 3 phase so excuse my ignorance.
But this one horse motor that's pulling 16 amps would be pulling 16 amps if it were wired for 240. How could a 3 phase one horse motor only pull 7.2 amps?
tallyho8 said:The difference is that a 110v line has one 110v line and a neutral and pulls 16 amps on that one line.
The 220v line is actually two 110 volt lines in different phases and the motor pulls 8 amps on each line.
The 3 phase uses 3 lines in different phases. Now, someone explain the way to figure the amps on 3 phase to us.![]()
BillyP said:Yes I understand the amp draw...120 volt motor = 16 amps on line 1 240 volt motor = 8 amps on both line 1 and 2 which = 16 amps. What I don't get is how a 3 phase motor can pull less amps through the meter. Is it as simple as wire size and voltage drop?
BillyP said:Yes I understand the amp draw...
120 volt motor = 16 amps on line 1
240 volt motor = 8 amps on both line 1 and 2 which = 16 amps.
What I don't get is how a 3 phase motor can pull less amps through the meter.
Is it as simple as wire size and voltage drop?