Hello everyone! First post on my part, so please forgive any "noob" stuff! I'm trying to replace a fan motor in a vintage NuTone kitchen hood vent, from the 1960s. It has a 3-botton control for the fan motor, however it's equipped only with a two-prong plug for the old motor. That old motor DID support two speeds via that plug, but in looking a new replacements, I see 3-wire motors. What am I missing here? What motor-type should I be looking for? The controls on the vent-panel look like this: https://thumbs.worthpoint.com/zoom/...nutone_1_e5f91b14fb1261c6ae7d3170dde7cf4c.jpg

 

Welcome to AAC, Jim.

I suspect in the 60's, 3-wire was not required. They are still as safe now as they were them. Have any deaths inyour household been attributed to that fan? (I doubt it.)

In 1969 Underwriters Laboratories mandated three-prong plugs on major appliances for safety. At that time, only half of the receptacles in US homes were three-prong.

You may not be able to find a 2-wire replacement. The third wire is probably green. The white is grounded, but is not consider ground. Think about it. Is someone likely to be in bathtub and touch the device?

Edit: If your house has been updated to 3-wire, you may want to run a third wire. I have a 1950's home that is knob and tube, 2-wire. In the basement, I ran a ground wire for my tools that have large meta surfaces that I touch. Upstairs, fixtures and so forth have only 2-wires connected.

 

Welcome to AAC, Jim.

I suspect in the 60's, 3-wire was not required. They are still as safe now as they were them. Have any deaths inyour household been attributed to that fan? (I doubt it.)



You may not be able to find a 2-wire replacement. The third wire is probably green. The white is grounded, but is not consider ground. Think about it. Is someone likely to be in bathtub and touch the device?

Edit: If your house has been updated to 3-wire, you may want to run a third wire. I have a 1950's home that is know and tube, 2-wire. In the basement, I ran a ground wire for my tools. Upstairs, fixtures and so forth have only 2-wires connected.

Hah! No deaths! I should clarify, the "2 prong plug" I speak of is built into the fan enclosure. The enclosure itself is hard-wired into the house, as you'd expect. I suppose my main question is: "How does this hood-vent switch support a dual speed motor with just 2 wires?" Modern single speed motors have 2-wire plugs, but will only support (of course) 1 speed. Modern 2-speed motors appear to have THREE wires, to support that 2nd speed setting.

Sorry if I'm not making sense. Not enough caffeine yet.....or maybe too much?

 

Hah! No deaths! I should clarify, the "2 prong plug" I speak of is built into the fan enclosure. The enclosure itself is hard-wired into the house, as you'd expect. I suppose my main question is: "How does this hood-vent switch support a dual speed motor with just 2 wires?" Modern single speed motors have 2-wire plugs, but will only support (of course) 1 speed. Modern 2-speed motors appear to have THREE wires, to support that 2nd speed setting.

Sorry if I'm not making sense. Not enough caffeine yet.....or maybe too much?

Attached is a pic of the current plug, built into the enclosure. A volt-meter test shows 118V AC, on low or high. I'm just...puzzled, but I'm sure I'm just missing some chunk of information.

 

My bathroom NuTone fans in a house built in 1993 are all two-pronged. Don't worry about it. Use the L1 and Neutral. If that worries you, call an electrician. Don't risk someone's life for $100. Or is that $200 today?

 

My bathroom NuTone fans in a house built in 1993 are two-pronged. Don't worry about it. Use the L1 and Neutral.

Ok. One last question then if you don't mind - this time for my intellectual curiosity - HOW is the NuTone panel able to "Tell" the motor to fun slow or fast? Something like a potentiometer, but with just two settings?

 

Ask NuTone or RTFM. (I just learned 2 days ago what that means.)

 

I do wish I had the manual.

 

Something like a potentiometer,

Similar to a ceiling fan control.
Maybe a tapped transformer.

 

It has a 3-botton control for the fan motor, however it's equipped only with a two-prong plug for the old motor. That old motor DID support two speeds via that plug, but in looking a new replacements, I see 3-wire motors. What am I missing here?

Check how 3-button speed control is wired. I guess they used capacitor(s), like these:
https://good-appliance.com/products/97017406-97017407-broan-nutone-range-hood-speed-capacitors

 

Check how 3-button speed control is wired. I guess they used capacitor(s), like these:
https://good-appliance.com/products/97017406-97017407-broan-nutone-range-hood-speed-capacitors

AHAHAHAH! Now that makes sense. Thank ya very much!