Results 118 to 123 of 123
-
08-11-2007, 03:37 PM #118
I don't know about all that crap Joe....but dang man......quit grabbin bare wires!!!
___________________________________________
-
08-11-2007, 06:09 PM #119
I swollowed a penny, a nickle, and two dimes. Next week I will be invunerable!
-
08-13-2007, 12:47 PM #120
Professional Member*
- Join Date
- Apr 2004
- Location
- Des Plaines,IL
- Posts
- 956
-
08-13-2007, 03:50 PM #121
Professional Member
- Join Date
- Dec 2006
- Location
- Long Island, NY/ Columbia, SC
- Posts
- 223
-
08-13-2007, 10:14 PM #122
Professional Member
- Join Date
- Jan 2003
- Location
- San Jose, Ca
- Posts
- 2,089
Good God!! yes when you disconnect one phase from a running motor on 3 phase you will still have 460, but it will be only single phase. If the motor is turning and the overloads or fuses do not trip it will keep turning but the motor will over amp and let the smoke out it if it has any kind of load. It is not the voltage alone that makes the motor turn but the difference in phase angle,
On 480 three phase power the voltage between A and B is 480 vac, B and C is 480, and C and A is 480. And A, B, Or C to ground or neutral is 277 vac.
Out of curosity if you think it is voltage that keeps a motor turning, what happens to the speed of a 208 vac induction motor when hooked up to 480?Old snipes don't die they just loose their steam
-
08-14-2007, 07:06 AM #123
No, and I don't want to be. (in answer to OP)
I have bumped one leg of it as I was reconnecting the LV side of a compressor contactor.
Also, I probably drive newbies crazy because I always tell them the following story as I go on and on about checking for voltage even if you are the one who disconnected the power, or no matter how much you think you trust someone who disconnected it.
I was replacing a blower motor on an old 48DR (RTU) and I shut off at the disconnect, climbed on top after removing panels and proceeded to replace the motor.
Almost ready to start it up, I checked in electrical panel and for some reason my meter told me that there was at least 260 to gnd. !!??
The disconnect had broken and one of the knifes was not turning with the handle--it was stuck in the hot side.
So I say ALWAYS check for power even after you disconnect.
One more story to drive y'all nuts--
brand new Lennox RTU with sectra system. One zone controller giving us problems. Shut off power and replaced controller. Now, nothing is working right. Come to find out the brand new disconnect did not disconnect, as it repeated this action in subsequent trials, and the 3000$ controller in the RTU was toast. Still had 160V to ground on one leg, and the OCC lamp was lit .
Had enough? There was this one time....
It's great to be alive and pumping oxygen!


Reply With Quote
