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Hello all, 

 

I have this new motor for a blower I'm using.  The wiring harness attached has four wires. Red, black, green, and white. What might this suggest? Two speeds? If so how would or what would be the best way to go about getting it all together? 

Thanks a bunch 

Dayne 

Non electrician

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I havent. Its Sunday so I didn't bother. I browsed a couple product catalogues and did some internet searches for the model number and how it would typically be used. No luck yet. Figured I'd come here to ask for help.  It was of similar size to the one that was on the blower unit when I got it.its   0.12 A less than the one it had but 5000rpm instead of 3600

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Steve is a certified master electrician and has forgotten more than I will ever know. My late FIL was a master electrician and taught me a lot before he passed away.

It's not about a vote of confidence, it's about trying to keep you safe. We would hate to hear you wound up in the ER because you got hurt or worse. I know a lot about electric and wouldn't attempt to wire that motor without contacting the manufacture for instructions.

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Hopefully this link is allowed.

A lot of motors like that are used in various home furnaces. I've replaced a bunch of them... but no two are ever alike.

As far as I can tell, it's either a two speed motor, or reversible. Most reversible motors have a two piece connector that allows you to flip the connector and thereby flip polarity or rotation.

In the US- 

Green is always your ground. It will go the the bare copper wire in your home's wiring, or to the ground lug on a 110v plug.

White is always your neutral. White wire goes to white wire.

Black is your hot. It will go to whatever speed you want to run. In a multi speed furnace motor, that can be black, red, blue, yellow wires. Generally, black is your highest speed.

Most motors have a wire color code label, or at least a sheet of paper that come with them (new motors in box) that tells you which wires are which speed settings.

Good luck.

Fasco Motor Wiring 1.jpg

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You might have some mechanical considerations to think about as well.  In addition to the potential for added vibration for a fan that is operating at 40% more RPM (potentially leading to imbalance and excessive noise and/or motor mounting/impeller damage - you did pick a motor with exactly the same mounting configuration, right?), you may have issues with motor power.  Per typical fan laws fan output in airflow is directly related to RPM, so a 40% increase of RPM will give 40% more air.  However the power required to operate at that RPM is cubed!  Since motor power in a single phase motor is directly related to amperage draw, and your substitute motor has lower draw, you likely don't have enough motor to run that fan at that RPM.  I'm not sure of the electrical aspect attempting to run the motor at the higher RPM (which I believe is related to AC supply frequency in synchronous motors, but I could be wrong), but I doubt it would be good.

Why did your first fan motor fail?  Perhaps you should look into that before thinking about replacement.

See the following for an illustration:  https://www.engineeringtoolbox.com/fan-affinity-laws-d_196.html  (specifically the chart that illustrates a change in wheel velocity while maintaining wheel diameter.

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Knowing why a motor has failed is the key to successfully replacing it IMHO.  There are plenty of common reasons for fan motor failure in a blacksmith shop, including but not limited to: incorrect wiring, incorrect voltage applied, incorrect fan sizing for the system it's connected to, attempt to use standard dimmer switches for motor's that don't work with same, metallic dust or debris getting in the motor windings, bearing failure, impeller misalignment and scraping, in-airstream motor overheating...  Each of these problems requires a different solution.  We don't even know if you are using this fan/blower for a solid fuel forge, powered exhaust or forced air gas forge.

My recommendation would be to get an entirely new blower, correctly sized and specified for the intended use, with the limited information you have given us.  Otherwise I believe that you will be throwing good money after bad.  If the motor was bad when you bought it why aren't you going back to the original supplier?

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Fair. It's a LP gas forge.  With a fairly small ribbon burner. Everything I get is either reused or recovered from somewhere. Kijiji included. I was hoping to "scab" something together for free and see what I could come up with before I went and dropped $90-180 on store bought item. Generally this technique has worked for me so far but  there does eventually come a point when I move on and just buy one. When that happens it will be for a newly rebuilt forge. I recently started taking this whole forging and small business thing a bit more seriously now that it's been a hobby for 8 years.  I've only spent about six months in a working bs shop. All I can say is the blower I have wasn't enough at 1600 rpm. 

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Well from one photo I can say on the plus side it appears to be a high pressure/low CFM configuration blower (with vanes instead of a squirrel cage), not a low pressure/high CFM one.  This would typically be more appropriate for your forced air LP forge.  OF course I"d have to see inside the blower to be sure.  On the negative side it is not obvious that the motor was ever mounted correctly, at least from the photo you show.  I'm confused that you said 3600 RPM in your earlier post and now you say 1600 RPM.  What do you mean about "not enough" blower?  You know you can makeup for blowers without sufficient external static pressure (ESP) by upsizing your ductwork, right (or the outlet ports on your ribbon burner, if necessary)?  Also if the motor has been replaced your should always check rotation direction.  If backwards can severely reduce output.

If I were trying to locate a cheap blower for a forge I would look to find a scrapped newer condensing gas furnace or boiler in the 150-250 MBH range.  The gas train blowers on those are less likely to be a failure point than the heat exchangers or ignition system.  Most of those blowers are even fitted with ECM motors and can be speed controlled.  They are often plastic bodied, but you aren't putting them in the forges...

What did your blower come from?

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No, that's catastrophic scenario. Guys, I appreciate any help I get. This is a super useful place to learn countless things from smart people. I'm not splashing around in a puddle with a wire hanging outta my.... 

The blower was from a pile of scrapped furnace equipment outside a neighboring shop. The motor that was on it was a 3600rpm.  I had an old barn fan with 5/16 shaft that fit the hole.  It was 1600 rpm.  That wasn't enough, meaning I had my regulator at maybe one psi to get the mixture right. It wouldn't have gotten hot enough to weld like this. Thanks I'll look into those. I met an HVAC guy on site today too!

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Yes, as stated less than half the RPM gives at best less than half the CFM.  Note that pressure isn't an accurate measure of gas flow unless you specify the outlet orifice.   1 psi isn't much through a 0.030 mig tip.  However it is quite a bit more through a 1/8" tube.  For a forced air, gun, burner you don't need an orifice,  unless you are using it to induce mixing.  Of course you forge design will determine how much burner you need.

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