Please Eric, what's the maximum Goldquest coil current ?

[Kev]

Hi Eric,
I've tried to find a datasheet for the Kynar coated wire used in the V1 GQ coils, but all in vain so far. I've used this same wire in some of my home brew coils too.

I would like to add another coil drive transistor without series resistance, parallelled with the existing transistor. Because I strobe the 4017 with a micro, I can use any two of the 3 ORed coil drive outputs for other purposes, and would like to try a 200us pulse at 2 amps along with several 40us pulses.

I believe this gauge of wire is rated nominally to about 1.1 to 1.2 Amps, is this correct?

If I calculate the RMS value for my pulse train/frequency and ensure it sits below 1 Amp or so will I avoid the lead melting in your production coil?

Thank you very muchly in advance.
Regards
Kev.

 

[Eric Foster]

Hi Kev,

I have run a Goldquest coil on a Goldscan with no ill effects, other than it gets slightly warm to the touch. I now use the equivalent PTFE insulated wire, which is good for high temperatures anyway. You often see it on Ebay, where I bought a 10,000ft reel. If you ever got near the temperature to melt the lead shield, then the whole coil and shell would look like one of your hot bubbling mud volcanoes. I'm not sure how Kynar wire compares to ptfe, but with pvc wire that I have used in the past, the coil's characteristics change as it warms up. You can see this by looking at the RX waveform on a scope. The overshoot on the recovery waveform changes considerably. Must be temperature dependance of the dielectric constant.

Eric.

 

[Kev]

n/t