The voltage drop requirements were clarified as they relate to emergency starting.
Жүктеу.....
Пікірлер: 6
@iaov Жыл бұрын
Most 3 phase 480 motor contractors use 115 to pull in the contractor.... so we are dealing with 2 different voltages here. Correct?? 15 % for Coil voltage , 5 % for mortar voltage?? This almost seems backwards to me in that as long as the contractor pulls in without chattering, the motor will turn on a fairly reduced voltage.... may be a dumb question but I’m curious enough to risk it!❤
@denverbraughler3948
Жыл бұрын
He really meant contactor, not contractor. And you really meant motor not mortar. Of course, a motor has a rotating magnetic field. A solenoid doesn’t.
@garbo8962
Жыл бұрын
If a fire pump motor had a 15% voltage drop the 120 volt control circuit would be close to that ( depending on length of wire from fire pump control panel to motor ) . Years ago Allen Bradley used to supply think they called it the seal contactor voltage.( big name for lowest voltage that a starter will pull in without chattering ). Several times I have came across plain Jane NEMA motors feed by 208 volts while motor starter had a 240 VAC coil. During the day have measured the 208 at load side of starters to be 196 volts. ( over a 17% voltage drop ). 120 volt control circuits a lot safer for people working on equipment.
Well….the issue is that the 115VAC panel shown is a diesel fire pump controller. A contactor is used in a higher voltage electric motor driven fire pump.
@willlock3644
Жыл бұрын
He addresses that regardless… The paragraphs deal with the contactor….VD across that…
Пікірлер: 6
Most 3 phase 480 motor contractors use 115 to pull in the contractor.... so we are dealing with 2 different voltages here. Correct?? 15 % for Coil voltage , 5 % for mortar voltage?? This almost seems backwards to me in that as long as the contractor pulls in without chattering, the motor will turn on a fairly reduced voltage.... may be a dumb question but I’m curious enough to risk it!❤
@denverbraughler3948
Жыл бұрын
He really meant contactor, not contractor. And you really meant motor not mortar. Of course, a motor has a rotating magnetic field. A solenoid doesn’t.
@garbo8962
Жыл бұрын
If a fire pump motor had a 15% voltage drop the 120 volt control circuit would be close to that ( depending on length of wire from fire pump control panel to motor ) . Years ago Allen Bradley used to supply think they called it the seal contactor voltage.( big name for lowest voltage that a starter will pull in without chattering ). Several times I have came across plain Jane NEMA motors feed by 208 volts while motor starter had a 240 VAC coil. During the day have measured the 208 at load side of starters to be 196 volts. ( over a 17% voltage drop ). 120 volt control circuits a lot safer for people working on equipment.
@iaov
Жыл бұрын
@@denverbraughler3948 thanks denverbraughler!! Frickin spell check☹️
@willlock3644
Жыл бұрын
Well….the issue is that the 115VAC panel shown is a diesel fire pump controller. A contactor is used in a higher voltage electric motor driven fire pump.
@willlock3644
Жыл бұрын
He addresses that regardless… The paragraphs deal with the contactor….VD across that…