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External AC control box.

A project log for Grizzly G0704 CNC Conversion

Joining the ranks of the Chinese made Grizzy G0704/BF20 conversions.

charliexcharliex 08/19/2014 at 17:260 Comments

Now that Siggraph is over and I finished the lightstage, and my HD oculus rift modification, I can hopefully get some free time to work on things again at a decent rate.

My PCB CNC has a useful box that switches the vacuum on and off and since its noisy as all heck, i really want that, i want to be able to control the spindle too.

Since the motor is an inductive load, I am not using a zero volt crossing SSR, instead one that switches immediately, placed the order last night with digikey. I'm opting to go for a Crydom D2450-10 from dk vs a the cheapos on ebay since the fail on an SSR is either always on or big bada boom. So might as well do what I can, it is $45 vs $20. 

Basically I have a power in, and C19-15 out, the controller i'm using is already opto isolated. It's very basic.

Heat sink is a must, calculate for the in rush current ( 6 to 10 times the normal load )  and appropriate gauge wiring, I'll fuse it for the load versus the rating of the SSR

I may build two boxes, one with a zero crossing, and the one without. After that i'll look at motor speed control, very simply at first by replacing the pot on the board with a frequency to voltage converter.

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