Quote:
Originally Posted by wa2ise
If the heater string adds up to around 84V, you can use a rectifier diode, without any filter cap, to effectively drop the 120VAC line. This saves the energy that would be wasted as heat. Remember, it's power = volts squared over resistance. The diode cuts the power in half, and the effective voltage is 120V times the square root of 2 (from the half) which then = 84V.
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You missed the part where it is mentioned that the Ballast in the CTC2B (a parallel heater transformer powered set) is used as a DC B+ divider....It has to remain a resistance based divider....Unless of course nick wants to go with LM317 DC to DC regulators. For the drop he'd need at least 4 in series (I've ran those chips in series as well as parallel before) to safely drop 115V (each device can only drop 40V max between input and output terminals). The biggest hurdle of using the LM317 is what to use as a ground reference...You might be able to keep the 430 ohm and reference the whole shebang to the centering terminal (thus replacing only the 800 ohm with LM317s), but if you want to eliminate all resistors you would need a ground reference.
11-08-2016, 03:53 PM
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