Timers are expensive!

I know that my electricity costs are right as far as the calculations go. But every timer I have seen says its 1/3 hp motor. I find it hard to believe too, but thats what their ratings say, not what I think they are using. If all 250 watts of power are used to simply turn the dial, then very little power would be lost as heat.
 
Timer energy useage is not measured in horsepower. Are you sure you don't mean that the timer is rated for up to 250 watt of lighting used...or rated for a maximum of a 1/3 horsepower motor?
 
joephys, I think I got it...that timer may really be rated for 1400W or 1/3hp.

You are correct, sir: 1/3hp jibes with 250W. However, single-phase AC powered fractional horsepower motors used in appliances (or power tools) have really high startup power requirements. Flipping them on will pull much, much more than 250W for that short while until they accelerate up to operating speed, especially if they are already under a physical load during startup. That's why the timer will be rated for 1400W constant draw with a 115V voltage rating (about 11 to 12 amps), but only 1/3hp for a 115VAC motor due to its possible startup requirements.

Just my best swag on the question. I could be completely off the mark. Any electricians out there?

v/r, N-A
 
My controllers are X-10, and are digital.

I believe that several posters in this thread are confusing the timer's power usage, with the power usage of those devices plugged into the timer. Those are two separate and distinct usages. You could have a 7.5W night light plugged into a rotary timer and the combined power usage of the unit and the light would be all but undetectable on the monthly bill. Or you could have 1000W of light plugged into it and use a kilowatt every hour. My controllers do not directly power the lights, they only turn them on and off. The power usage from my lights could heat some homes. The light power usage occurs whether you turn them on and off manually or a timer or controller does that job. When you talk about a timer's power usage, you cannot include the power used by the controlled devices.
 
Right, I am only refering to the actual timer its self, not the lights or anything that is plugged into it.

I just looked at the timer. Its rated at 15A at 125V so thats 1875W. That is the ammount of power that can go through the timer to the lights or what ever it is that you have plugged into the timer. This isn't the issue.

As far as what N-A said, the ammount of start up time is very small, on the order of miliseconds. I guess I can kind of see why they would list that, but if that is the case they should list the opperating power usage too.

Maybe I should just rig an ammeter up to it and figure it out once and for all.
 
I just checked mine, its rated at 1/3hp -- meaning it can have up to a 1/3 hp device connected to it. These things use such a small amount of power that they don't even bother to put it on the label. I doubt if you could even measure it with an electricians amp-meter, and the cost for a month is likely in the 1cent range.
 
maybe the 250 watts is how much energy it uses only when it turns the lights on/off, and at other times it uses not much energy?
:rolleyes:
 
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I've got a couple timers by Intermatic that replace the normal toggle switches installed in household wall-mounted switchboxes. These use a single AAA battery for all timing and switching duties. No house current is used except that which flows through the switching to power the connected house lighting.

My batteries have been going for a year now on these. As quenton said, digital timer power requirements are truly miniscule.

v/r, N-A
 
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