Why is this electronic timer not working?

[Mr. Apollo]

I have a bathroom fan that I wanted to attach a timer to. I like the Leviton Decroa electronic timers so I picked one up. Now, because I don't have a neutral wire, I got the 6560M (http://www.leviton.com/OA_HTML/ibeCCtpItmDspRte.jsp?item=6869&section=17139). It's rated at 500W and 5A. Leviton says if you're using it for a fan then you should use the next model up (http://www.leviton.com/OA_HTML/ibeCCtpItmDspRte.jsp?item=6861&section=17139) which is rated for 1000W and 20A. However, since I don't have a neutral wire in the junction box and becuase it's a very small Broan unit (1.1A) the guys at HD said that this would be more than enough. Well guess what, I hook it up as per instructions and the indicator lights turn on but when I got to activate the fan it barely moves and makes an audible buzzing noise. I've tried two different timers both with the same result so I know it's not a bad unit.

What is causing the problem? Is it becuase the unit cannot deliver enough power to the fan? The switch is rated for 5A and the fan motor only says 1.1A.

[SPARKY]

Taken from the link you provided, at the bottom it clearly states.
Some of the guys at HD are salesmen not electricians.
6560M-A


Description
500W, 120 Volt AC 60Hz, Single-Pole, Decora, Four Preset 10-20-30-60 Minutes, Electronic, Incandescent Only Timer, Neutral Not Required - Almond


Product Features
Switch Type: Single-Pole
Timer Type: Four Preset
Style Name: Decora
Time Range: 10-20-30-60 Minutes
Load Type: Incandescent Only
Load Rating: 500W
Voltage: 120 Volt AC 60Hz
Wire: 2
Neutral: Not Required
Wallplate: Included
Color: Almond
Standards and Certifications: UL/CSA
Warranty: 2-Year Limited


Features and Benefits
FOR INCANDESCENT LOADS ONLY!
For exhaust and bathroom fans use the 6260M-A Timer

[Mr. Apollo]

Features and Benefits
FOR INCANDESCENT LOADS ONLY!
For exhaust and bathroom fans use the 6260M-A Timer
Yeah I read that but they said it would be fine. :(

OK, out of curiosity, how come it doesn't work? To me , a layman, "the numbers" seem to indicate that it will work but obviously it doesn't. Why is it suitable for incandescent loads only but not for something like a fan motor?

[Mouse]

I would guess that it's made for a heat lamp.

It does not allow enough voltage to pass through it to run a motor (and a lamp too??).

[Mr. Apollo]

I would guess that it's made for a heat lamp.

It does not allow enough voltage to pass through it to run a motor (and a lamp too??).Yes! It actually says "perfect for heat lamps" on the box. Hmm so it's a voltage issue, that makes sense considering the fan was moving but very, very slowly.

[SPARKY]

It's an Amp issue.
A 75 watt bulb uses 0.6 amps.
The fan running uses 1.1 Amps, the start-up of the fan could be greater combined with the light exceeds the limit of the timer.
I can't find a load rating for that dimmer but will handle 500 watts.

[Mr. Apollo]

It's an Amp issue.
A 75 watt bulb uses 0.6 amps.
The fan running uses 1.1 Amps, the start-up of the fan could be greater combined with the light exceeds the limit of the timer.
I can't find a load rating for that dimmer but will handle 500 watts.The fan and bathroom light are on separate switches so the electronic timer only controls the fan.

[SPARKY]

The timer doesn't have a load rating, so it can only handle incandescent bulbs.
A fan has a much greater load then a bulb. Thus an amperage issue

[Mr. Apollo]

The timer doesn't have a load rating, so it can only handle incandescent bulbs.
A fan has a much greater load then a bulb. Thus an amperage issueOK, forgive me for asking so many questions but I just want to understand this. Now the fan motor says 1.1 amps but the switch is rated for 5 amps. Are you saying that the fan may draw more than 5 amps?

[SPARKY]

I can not find a 5 amp rating for that dimmer 656M-A on thier site. If it's on the pachage itself it may by a missrint.
Mayby they missed a decimal point 0.5 amps ?
Although the 620M-A has a load rating of 1000W / 20A 1HP-120V

[Mr. Apollo]

This PDF (http://assets.twacomm.com/assets/pdf/16562.pdf) is a Leviton catalogue and it shows the 5 amp capacity (page 18). However, it does classify it as a "lighting control timer" and the 20 amp model as "motor load rated". I know this is going over the same point, and I recognize that you're right, but I am just wondering why the other timer couldn't handle the motor.

[SPARKY]

The fans motor start up load must draw more then 5 amps I'm guessing.
Most do a furnace, AC, fridge, ECT...
Even though it's small the draw might be a factor.

[Mr. Apollo]

The fans motor start up load must draw more then 5 amps I'm guessing.
Most do a furnace, AC, fridge, ECT...
Even though it's small the draw might be a factor.OK,that makes sense. Thanks for taking the time to explain evertyhing. :)

[AMD]

OK, forgive me for asking so many questions but I just want to understand this. Now the fan motor says 1.1 amps but the switch is rated for 5 amps. Are you saying that the fan may draw more than 5 amps?


When there is no opposing magnetic field on an inductor, the resistance is much lower than in typical operation. Consequently, motors require four to six times the rated current during startup.

The other thing is that any electronic timer which doesn't require a neutral gets its power from the circuit it is controlling. (Powerstealing in other words) That's all fine and good until an inductive or capacitive load is applied which creates a phase shift between voltage and current.


http://www.google.ca/search?hl=en&q=How+motors+work&meta=

[Mr. Apollo]

The other thing is that any electronic timer which doesn't require a neutral gets its power from the circuit it is controlling. (Powerstealing in other words) That's all fine and good until an inductive or capacitive load is applied which creates a phase shift between voltage and current.
What happens when a load is applied (I assume we're talking about motors here)?

Here's another question, what about those devices that allow you use a 3 wire switch on a two wire setup? I've seen them mostly in relation to home automation stuff but basically their a little box that goes in the junction box and allows you to use a switch that requires a neutral on a setup that has no neutral in the switch box (obviosuly there's one in the junction box where the device you wish to control is located.)

[Mr. Apollo]

Well the 3 wire to 2 wire converter says that it can be used on "480W incandescent loads or an 11 amp inductive load" so it can be used for "ceiling fans and small appliances" now I just have to see if it'll work with the timer.

[AMD]

What happens when a load is applied (I assume we're talking about motors here)?

I don't know anything about those lighting automation systems.


A motor draws several times its running current during startup, which can not be easily handled by sensitive electronic devices. Due to the characteristics of AC motors, operation causes the voltage and current waveforms to go out of sync; this may or may not cause a problem with electronic timers which do not require a neutral.


As long as all the current that goes to the motor also powers the electronic timer (see picture), you'll have the same problem unless the switch is specifically designed for that purpose. Timers which require a neutral draw the electricity in parallel to the device that is being switched, so they are unaffected by small startup surges or phase shifts caused by motors.

[Mr. Apollo]

I don't know anything about those lighting automation systems.


A motor draws several times its running current during startup, which can not be easily handled by sensitive electronic devices. Due to the characteristics of AC motors, operation causes the voltage and current waveforms to go out of sync; this may or may not cause a problem with electronic timers which do not require a neutral.


As long as all the current that goes to the motor also powers the electronic timer (see picture), you'll have the same problem unless the switch is specifically designed for that purpose. Timers which require a neutral draw the electricity in parallel to the device that is being switched, so they are unaffected by small startup surges or phase shifts caused by motors.
Ah OK, that makes a lot of sense. It would also explain why the home automation stuff needs a neutral too.

[mlefebvre]

I have a very similar situation, except I have an incandescent only timer switch rated for 300w that I would like to use to control a florescent fixture. I have not tried it yet, but will it work? If not, why not? Thanks,

Mark

[SPARKY]

Can you use a dimmer with fluorescent light fixtures?

Yes and no. Yes, there is a specially-designed dimmer switch that will work with some fluorescent fixtures. However, this type of dimmer is "ballast-dependent", meaning that each brand of fluorescent dimmer will only work with certain ballasts from certain manufacturers. In other words, trying to find a dimmer to match your fixture may be a mind-numbing chore. The ideal situation is to choose the dimmer and the light fixture together to assure compatibility. Also, these dimmers will not work for incandescent fixtures. You cannot mix fluorescent fixtures and incandescent fixtures on the same switch.

The "No" part of this question is that the "conventional" dimmer switches you can purchase at the hardware store are designed for incandescent lighting only, not fluorescent lighting. If you attempt to use them, the fluorescent fixture may work but only in the full-on position, if at all.

[AMD]

Using a convectional dimmer on fluorescent lighting can seriously reduce the efficiency of or even damage the ballast even if it's set to "full on".

Dimmers do not work by just reducing the overall current flow to the fixture in a linear manner; they very quickly switch on and off at different points of the AC (alternating current) waveform.

Please see http://home.howstuffworks.com/dimmer-switch.htm