Or a BT137??
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Or a BT137??
-Bert
The glass is not half full or half empty, Its twice as big as needed for the job!
http://foamcasualty.com/ - Warbird R/C scratch building with foam!
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Hi, Bert
Halas it uses the Counter EMF of the motor ...I recall a SCR switching circuit to control the avarage voltage across a motor for a simple speed control.
The trick here is to use PWM and sample the wire resistance ( needs wire with a PTC ! ) while PWM is off ...
Alain
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Why insist on using 32 Bits when you're not even able to deal with the first 8 ones ??? ehhhhhh ...
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IF there is the word "Problem" in your question ...
certainly the answer is " RTFM " or " RTFDataSheet " !!!
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What is PTC?needs wire with a PTC
Dave
Always wear safety glasses while programming.
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Thermistor I guess. ICL
Last edited by mister_e; - 27th January 2011 at 17:37.
Steve
It's not a bug, it's a random feature.
There's no problem, only learning opportunities.
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Re: controlling a hotwire
Hello all, I am back to trying to get this done. Any suggestions on the transformer in the melabs example? I don't need the power supply side, so really I guess I just need the zero crossing sync.
So basiclly, a logic level TRAIC (as linked by Dave) connected to an output and a way to detect the Zero crossing is all I need, Yes?
-Bert
The glass is not half full or half empty, Its twice as big as needed for the job!
http://foamcasualty.com/ - Warbird R/C scratch building with foam!
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Re: controlling a hotwire
Exactly.Originally Posted by cncmachineguy
The transformer must be rated for at least the maximum power you would expect to use plus a margin for safety. Since the VA rating defines the power, you could be very adaptable on the choice of transformer in terms of volts and current but, generally speaking, keeping the volts low (<24VAC) and the current high (probably around 3A to 5A) is safer for the user.
There would be a quite large selection available on the likes of eBay if you search.
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Re: controlling a hotwire
half asleep, but here is my beginning. Looking for some help here if anyone wants to help me fix this
-Bert
The glass is not half full or half empty, Its twice as big as needed for the job!
http://foamcasualty.com/ - Warbird R/C scratch building with foam!
|
Re: controlling a hotwire
Positive Temperature Co-efficient
when the resistance increases as the temperature does.
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