beastmaster
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Buying a Variac
I was searching e-bay looking for a variac to use on a small mantel. I was over whelmed. What do I look for in a variac if I am using small(50ml to
1L)mantels. Are all of them basically the same? What amp. would I need? I prefer 110v. Could I run a PIC temp. controller with it or does the variac
do that on its own . Thanks. Beast
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The WiZard is In
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Quote: Originally posted by beastmaster  | | I was searching e-bay looking for a variac to use on a small mantel. I was over whelmed. What do I look for in a variac if I am using small(50ml to
1L)mantels. Are all of them basically the same? What amp. would I need? I prefer 110v. Could I run a PIC temp. controller with it or does the variac
do that on its own . Thanks. Beast |
Why not use up to date — sold state technology? A full range light dimmer.
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entropy51
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For the mantle you describe, you can't do better than a Staco variac that puts out 120/140 volts at 10 amps. There are other ways of doing it,
including a light dimmer from the hardware store. Unless you're doing precision fractional distillations, a variac will serve as well as a fancy
controller. Most of this, including PID controllers have been discussed in other threads. Magpie has given his design for a DIY temperature
controller. You could search, or you could just get a Staco or equivalent.
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not_important
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Adding on, 110v @ 10 A is good for mantles up to 1 kW. High wattage lamp dimmers work too, but sometimes through out a lot of RFI. Both depend on
the human to adjust them to set the power level to what is needed at that time.
Fancier ones, with PID being near the high end, can be set to automatically control the heat input based on input from a temperature sensor. Useful,
but probably overkill for smaller scale home lab work.
Almost all variacs do not isolate their output from the mains, so it may be worth investing in a ground current fault interrupter. These monitor the
current through both lines of the mains connect and if the current in them isn't equal because some is flowing from the 'hot' line to earth through
something, say the experimenter, the device cuts the power connection.
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