HT and Heater Center tap grounding

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hdahs
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HT and Heater Center tap grounding

Post by hdahs » Mon Jul 11, 2011 5:31 pm

I've noticed in a couple of pics, including the one in the wiki portion of this site. that on the Mercury P4550JT-G2 PT, the center taps for both the HT and Heater voltages are tied together and grounded at a common point.

Is this acceptable, or is there a more preferred method?
Thanks.

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neikeel
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Re: HT and Heater Center tap grounding

Post by neikeel » Tue Jul 12, 2011 7:52 am

Quite normal practise.

Important that the mains has its own dedicated ground and if you want silent running you can follow the 'Larry Grounding Scheme' or SDMs scheme to avoid ground loops.
Neil

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joey
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Re: HT and Heater Center tap grounding

Post by joey » Wed Jul 13, 2011 7:24 pm

There is no significant current flowing in the CT of the heater supply, so you can ground the CT where convenient. The HT CT however is a different story, and it must be grounded straight to the -negative lug of the DC reservoir cap if you are using two phase, no exceptions.

If you are using Bridge rectification, like in the 100W models, you can either opt out of using the HT CT, and heatshrink it off, or tie it to the junction of the series parallel cap bank used for the DC reservoir like marshall did for equal sharing, and better balance between phases, better than bleeders will provide (however bleeder have the benefit of well creating a discharge path, in this case you can do both and get the best of both worlds.)

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