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Topic: Power from 24VAC (Read 4 times) previous topic - next topic

packocrayons

Check out something like this:
http://www.hobbyking.com/hobbyking/store/__6320__TURNIGY_5_7_5A_8_42v_HV_UBEC_for_Lipoly.html
Used standard in the hobby industry, you can even find them up to 15 amp.
DON'T put AC current through it.

retrolefty

#16
Oct 05, 2012, 02:48 am Last Edit: Oct 05, 2012, 03:06 am by retrolefty Reason: 1

How about a Murata OKI-78SR-5/1.5-W36-C? The ebay one linked to looks like a clone of the Murata. The Murata is only $5, max Vin is 36V though so you could drop your 40V with a resistor between your bridge and the power supply. Dropping voltage from an unregulated transformer shouldn't be dramatic, it won't take much resistance (and thus wattage) to get a lot of voltage drop.



Think about that for a moment. At what current draw do you size the series dropping resistor for? If you size it for the maximum rated current of the regulator (so that the applied voltage to the power supply is 36 volts or less),  what value of input voltage will the regulator 'see' with little or zero current going to the load?

Left

tylernt

Quote
Think about that for a moment.
Ok you're right, I wasn't thinking. So, how about a low-watt, high-ohm resistor between + and - of the bridge output?

retrolefty


Quote
Think about that for a moment.
Ok you're right, I wasn't thinking. So, how about a low-watt, high-ohm resistor between + and - of the bridge output?


A non effective solution in any situation that I can see?

tylernt

Won't it drop a few volts regardless of the current the regulator is or isn't drawing?

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