how to measure "on time" of a motor


Old 11-30-13, 06:12 AM
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how to measure "on time" of a motor

I want to know how often my (propane) pool heater operates. I think the best way would be to wire a recording meter/timer of some sort to the 110v motor power terminal, but I can't find what I need to record the "on time". A simple "total minutes" of run time would be adequate, though it would ideal to have a graph of when and how long it runs (nice but not necessary if too many $$).

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Old 11-30-13, 06:46 AM
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Welcome to the forums! If you can find an old recording meter (industrial) like the ones used by your power company and wire it on the load side of your motor feed, then you can record its daily usage. Not sure if that is what you are looking for or not. You can find them on Ebay by searching "electric meter chart".

If you are diligent, you can place a simple hour meter on the load side and check it each evening to see how long it ran each day, and make a manual log entry.
Old 11-30-13, 06:55 AM
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Since it is 120 volt a Electricity Usage Monitor like the "kill a watt" should work for you. It will also even do the calculations of cost for you.
Old 11-30-13, 08:06 AM
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Are you concerned about how much propane you are using? I have used a 24 volt elasped time clock,found on ebay,connected in Parallel with my gas valve when the valve is opened the clock is energized and for every 1 hour you use approx.1gal of propane.
Just a thought
Old 11-30-13, 09:30 AM
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Any old electric clock like they use to sell with a synchronous 120 volt AC motor would work. You just need to check it every 12 hours.
Old 11-30-13, 10:44 AM
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Thanks for the ideas, folks. I think a simple hour meter is going to work fine. Reference the thought of connecting it to the gas valve... sounds like a good idea, but I think it would give me about the same thing as connecting to the blower motor. An old electric clock would work, but there's an hour meter on ebay for $13, and I don't have to keep track of it every day!
Old 11-30-13, 02:50 PM
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You can't connect it to the gas valve.
It will affect the heat anticipator.
Old 12-01-13, 11:40 AM
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Not sure it would if it is paralleled, with it worked fine for me.

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