B
Bob Engelhardt
- Jan 1, 1970
- 0
I have a nice electromagnet that I got on eBay (
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=200045827548 ). I'd
like to determine it's maximum current for 100% duty cycle. My plan is
to apply a small voltage (say 1 volt), let it reach steady state
temperature (minimum current) and calculate the temperature using
R=Rs[1+a(T-Ts)]. Increase the voltage and repeat until a maximum
temperature is reached. The magnet would be sitting on a piece of steel
approx. 12" sq x 1/4" thick, to simulate its intended operating
environment (power tool table).
1. Are there any flaws in this approach? Or should I say, what are the
flaws in this approach - there must be some.
2. What maximum temperature that I should use? I assume that the magnet
wire varnish would be the weak link, but that still doesn't help, much.
The magnet is potted in "polymer", would that limit the temperature
more than the varnish?
Thanks,
Bob
PS - if there's a better newsgroup to ask this question in, I'd
appreciate being pointed there, thanks.
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=200045827548 ). I'd
like to determine it's maximum current for 100% duty cycle. My plan is
to apply a small voltage (say 1 volt), let it reach steady state
temperature (minimum current) and calculate the temperature using
R=Rs[1+a(T-Ts)]. Increase the voltage and repeat until a maximum
temperature is reached. The magnet would be sitting on a piece of steel
approx. 12" sq x 1/4" thick, to simulate its intended operating
environment (power tool table).
1. Are there any flaws in this approach? Or should I say, what are the
flaws in this approach - there must be some.
2. What maximum temperature that I should use? I assume that the magnet
wire varnish would be the weak link, but that still doesn't help, much.
The magnet is potted in "polymer", would that limit the temperature
more than the varnish?
Thanks,
Bob
PS - if there's a better newsgroup to ask this question in, I'd
appreciate being pointed there, thanks.