Author Topic: Hall Sensors  (Read 11597 times)

Offline Mosey

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Re: Hall Sensors
« Reply #45 on: January 21, 2014, 12:10:24 AM »
Don,
Exactly what I don't want...to hide the components in a box! I want people to see the stuff because I think it adds to the interest in the engine systems.
But thanks!
Mosey

Offline Alan Haisley

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Re: Hall Sensors
« Reply #46 on: January 21, 2014, 12:14:22 AM »
Would a nylon washer be acceptable between HS and PCB? I don't have any mica.

Funny you should mention contact with the system, as I ponder the practicality of the exposed ignition. Is it a problem to leave it hanging out in the open, exposed to fingers or bumping into? Consider housing the ignition PCB in a plastic shield? Cooling?
Or is this overthink?
You know I hate those ignitions buried in a wooden coffin underneath the engines.
Mosey

Some place like Radio Shack would probably have the mica washers. If you want the heat sink to actually function you can't depend on the nylon washer. The mica washers are both much thinner and better by far heat conductors than the nylon.
You might build a rectangular tube out of big box store clear acrylic plastic. That way only the ends would be exposed at all and the parts would all be still nicely visible.

Alan
Near Raleigh, NC, USA

Offline Mosey

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Re: Hall Sensors
« Reply #47 on: January 21, 2014, 12:28:15 AM »
I might be able to find some mica in an old appliance that used heat like an iron or printer. I'll find it.
I could machine a plastic gem box to fit.Thanks,
Mosey

Offline Bezalel

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Re: Hall Sensors
« Reply #48 on: January 21, 2014, 12:32:10 AM »
Would a nylon washer be acceptable between HS and PCB? I don't have any mica.

Hi Mosey
 
short answer is no.
 
The mica insulator provides electrical isolation between transistor and heatsink.
At the same time provide good thermal conductivity.
 
Mica, nylon & PVC all are good electrical insulators but mica has good thermal conductivity, nylon & PVC don't
link below is an example of mica washer for T220 transistor, a very thin slice of mica 15mm x 19mm with a 3.6mm hole for the screw.
 
http://uk.farnell.com/multicomp/mk3306/insulating-kit-mica-to-220/dp/520214
 
Bez
Queensland - wet one day, humid the next

Offline Don1966

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Re: Hall Sensors
« Reply #49 on: January 21, 2014, 12:35:54 AM »
Mosey you want me to send you some mica insulators ?

Don

Offline Mosey

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Re: Hall Sensors
« Reply #50 on: January 21, 2014, 01:22:42 AM »
Yes, Don, please do. I found mica sheets at Amazon for repairing microwaves, but as you know I only need a couple of small washers, to fit 8-32 bolt.
I'll PM my address.
I'm making the standoffs from nylon rod, to fit 4-40 nylon bolts I will make. This is fun!
Mosey

PM Sent

Offline Mosey

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Re: Hall Sensors
« Reply #51 on: January 21, 2014, 04:25:23 PM »
I have remounted the HS onto the front of the PCB, instead of the rear, with a non-conducting screw, and it awaits a mica washer to insulate.Now that the HS is not in the circuit, can it be fastened to the engine with conducting fasteners? (can't find 4-40 screws in nylon) but  I will make them if I must.


Soon as I get the replacement transistor, were ready to fire. :zap:
Mosey

Offline Alan Haisley

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Re: Hall Sensors
« Reply #52 on: January 21, 2014, 06:36:29 PM »
Microfasteners has nylon 4-40 screws if you decide you need some.

Alan
Near Raleigh, NC, USA

Offline Mosey

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Re: Hall Sensors
« Reply #53 on: January 21, 2014, 07:14:15 PM »
Alan,
Thank you, will do. Homestretch, you know!
Mosey

Offline Don1966

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Re: Hall Sensors
« Reply #54 on: January 21, 2014, 07:29:21 PM »
Mosey your insulator is in the mail. I have also included a replacement transistor. Most transistor that are in package have the insulator for the transistor and screw.

Don

Offline Mosey

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Re: Hall Sensors
« Reply #55 on: January 21, 2014, 08:01:52 PM »
Thank you, Don. I'll probably turn it right around and send  it to you to make it work. We're getting 6-10 " of snow right now, so down to the basement I go.
Regards,
Mosey