+- Woodnet Forums (https://forums.woodnet.net)
+-- Thread: Three speed blower motor has me baffled (/showthread.php?tid=7324478)
Three speed blower motor has me baffled - MstrCarpenter - 11-01-2016
I have a reasonably large furnace to heat my shop. I"ve also been using the blower (with filters) to circulate the air when the wood stove is burning. It is currently set up so the blower runs continuously when the switch is on; regardless of the exchanger temperature or burner operation. The main reason it is set this way is because the starting windings on the blower motor are shot (I have to get on my knees and "manually" get it started in the right direction).
I have a newer three speed, 1/3 hp Dayton motor sitting on my bench in pieces. I would like to run it on high when the burner is on, then revert to low when the thermostat is satisfied. I think I can figure that out using a DPDT relay when I can get this thing wired correctly. The data plate wiring shows L1=white; L2= black-hi, blue-med, red-low. It also shows connections for an aux. start cap., and swapping yellow and purple wires to reverse rotation. I can only assume this motor originally came with a cable attached similar to this one https://www.amazon.com/Dayton-3LU77-Motor-3hp-Blower/dp/B001GBTBV6 which would make wiring this quite simple. (It actually looks more like the 1/2 hp motor #3K772 shown lower on that page or here https://www.amazon.com/Dayton-3K772-Motor-60hz-Belt/dp/B001GBNXRO/ref=pd_day0_328_3?ie=UTF8&psc=1&refRID=ZA4QHFDW6EKB6EDNWN3B ) All I have are four terminals on a plastic block located behind a small cover plate. There are four wires coming from the windings; red, yellow, blue and black. In my futile attempts to get this thing spinning clockwise I lost track of what went where. It is currently wired so L1 runs through a thermal protector and connects to red and yellow. L2 is connected to blue and a centrifugal switch that connects to the black. The motor does run with these connections in a CCW rotation, however; I didn't let it run but for a few seconds for fear of letting the magic smoke out!
So, finally, here are my questions. Are these connections o.k.? How do I change the rotation? Where would L1 and L2 connect for both high and low speeds? And as a super-duper bonus question, how would I connect a cable, if one should magically appear, with a white, black, blue and red wire, that may or may not have pairs of yellow, purple, and brown wires?
RE: Three speed blower motor has me baffled - Roly - 11-02-2016
Is it like this ? Roly
![[Image: 3-speed-fan-motor-wiring-diagram-l-a4a468426c16fbc3.jpg]](http://graph.darren-criss.org/2016/02/18/3-speed-fan-motor-wiring-diagram-l-a4a468426c16fbc3.jpg)
RE: Three speed blower motor has me baffled - MstrCarpenter - 11-02-2016
No, it's not really like that. If you zoom in to the data plate shown on the first link above, it shows the "external" wiring. I do not have that cable, nor do I have any idea how to connect it to the motor if I did. Basically I have to start with the four wires coming from the windings and connect them to the motor's terminal block and/or the centrifugal switch, and then determine how to get the three speeds and how to reverse the rotation.
RE: Three speed blower motor has me baffled - Roly - 11-02-2016
Not sure exactly what you need but try this LINK to Grainger's site for this motor and download the 2 pdf's for wiring and see if that is what you need. Roly
RE: Three speed blower motor has me baffled - TDKPE - 11-02-2016
(11-01-2016, 09:58 PM)MstrCarpenter Wrote: I would like to run it on high when the burner is on, then revert to low when the thermostat is satisfied. I think I can figure that out using a DPDT relay when I can get this thing wired correctly.A SPDT will work, using NC for low, and NO for high, energized when the thermostat calls for heat.
RE: Three speed blower motor has me baffled - MstrCarpenter - 11-02-2016
Roly, I printed out a similar diagram from Grainger for this motor. These diagrams are for external connections. I'm just guessing here but I think to start I will have to find out if one of the four winding wires is common to the other three. If they are, that would lead me to believe that I've found the three speeds; but I still don't know how the starting winding could still be one of the speeds if it shuts off when the motor comes up to speed.
Tom, the second pole would be used to keep the fan on high until the heat exchanger cooled down to the low limit setting. I'll check for continuity and resistance and report back.
Thanks for the suggestions.
RE: Three speed blower motor has me baffled - Roly - 11-03-2016
The two links you provided are for different types of motors. The first is a permanent split capacitor motor, the other is for a single speed split phase motor. Do you have a brand and model number of what you have ? If you have a centrifugal switch it is not a permanent split capacitor motor. Roly