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i have an older furnace and i need to change out the blower motor soon the original motor is getting bad. bushing bad. anyway i got another motor the same frame size but it came with 4 wires. white black red yellow or orange i can't tell. i did an ohm on them and i got w to black 2.0 w to yellow 3.2 w to rwd 3.9 but then from red to yellow 1.0 red to black 2.4 black to yellow 1.8 so they are connected inside also to have ohm's thru them.

i'm guessing the white is neutral and then i connect black,red,yellow for the speed. the motor has 1050 950 650 for speeds. and i'm thinking i need the 950 or 650 for the heat. i do not have a/c so any ideas the motor is a westinghouse 1/6 hp s# 310p631. thanks for any help on this bp.

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  • Hello, and welcome to Home Improvement. If the answer is helpful, please click the large check mark next to it to accept. And, please take our tour so you'll know how best to participate here. – Daniel Griscom Nov 16 '19 at 15:27
  • Can you post photos of the nameplates for the old and new motors, and the wiring diagram for the furnace for that matter? – ThreePhaseEel Nov 16 '19 at 16:41
  • It's all about the nameplate. – Harper - Reinstate Monica Nov 16 '19 at 18:51
  • i have 3 furnace motors and none have the wire diagram on them. must be a furnace thing. as most motors have some type of diagram on them or in the plate that covers the wiring points inside the motor. – corvairbob Nov 17 '19 at 16:10
  • That is unusual, NEMA requires the frame, voltage, fla, rpm and manufacturing name and model number. The colors are somewhat standard for these motors as for dual voltage 3 phase motors and some don’t put the wiring diagram on the name plate. – Ed Beal Nov 17 '19 at 16:25
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Red is normally low, yellow medium and black is high. There is normally a wiring diagram on the motor. Your old motor should have the RPM’s listed , but normally high is for AC . Make sure to wire nut the 2 unused wires. And yes white is the neutral.

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  • I have a similar system, with AC though, and the wiring is as Ed stated. – JACK Nov 16 '19 at 16:36
  • thanks jack that is about what i figured. but no there is no information on the motor. i know most motors have the pinout on them but i have 2 furnace motor and none have the pin out. on them. and the motor that came out i forgot to label the wires so i use that theory of whit being neutral and red and blac the speed and when i tried to run that motor on the bench connecting one wire to white for neutral and then touching the other wire either black or red i blew the power strip breaker on both tries. and that motor came out and was runing when removed. so i must have got it just in time. – corvairbob Nov 17 '19 at 16:08
  • Motors have a high inrush to get started, if the bearing/bushings are going bad that makes it even worse. – Ed Beal Nov 17 '19 at 16:19
  • yep i know about how motor operate but had to get some help with the furnace wires. furnaces are about the only motor i have come across that did not have the wire diagram on them. all the motors i have for furnaces do have all that info fo volts ph cy rpm etc but nothing for what wires are for what rpm. i figure the white was neutral but did not have a clue for the rpm. – corvairbob Nov 18 '19 at 17:09

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