Convert ac to dc

It is what it is. Do you really want to pay S&H for a $1 battery holder?

Hello again........ Reconnected the cap. and connected the pump...13.39 volts and it seems to run fine except the transformer gets to hot to touch......?????

Vic.......

you need a higher amp transformer.

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How much current does the pump draw? What is the max current the transformer is rated for?

Mark

is it OK without the capacitor?

The capacitor causes inefficient usage of the transformer which makes it get hotter that without.

If you need the capacitor you'll need to get a bigger transformer.

Bye. Jasen

I disconnected the cap. and took a reading with pump running,. The output is 10.98 volts at 1.9 amps. The trans is rated for 3 amps ac, and the pump rated for 2.5 amps dc. It all seems to be working so far. Thanks for all the input........Vic

I don't know what happened to my last post but it seems the original reposted itself. I will try again....I disconnected the cap. and took a reading with pump running.

10.98 volts at 1.9 amps dc at pump end. The trans is rated for 3 amp ac and the pump 2.5 amps dc. It seems to work fine so far no excess heat. Thanks again guys......Vic

I would still put a capacitor in cicuit-if you think the higher voltage is a problem put a smaller cap on it -but even then I would stay around 3000uf- when the motor runs I cannot see how you've ended up with such a high voltage-is the transformer rated for 220v on the primary -giving a slightly higher output on the secondary side of the transformer-you are measuring the output of the secondary in RMS AC volts or is it the peak voltage?

His value of 12.6 V must have been RMS AC, otherwise he could not have gotten 18.9 V DC with the rectifier & cap. (Which means his actual transformer output is more like 13 or 14 V AC).

At any rate, it seems things are working well for him, which is a victory for s.e.b. Using a 3300 uF cap caused his transformer to get pretty hot.

Mark

The unit has been running continously now for 5 days with no cap in the circuit. The trans does warm up but not to the point you can't touch it. Voltage varies 10.9 to 11.9 at 1.9 amps. I'll let you guys know how long it lasts ;-)....... .........Vic

It's geat it's going but could someone shed some light one what effect the capactor is having on the output of this transformer-why does the transformer run with increased heat?

The capacitor concentrates the current into pulses around the peaks of the rectified wave, and slightly fills in the valleys with its charge. This increases the RMS current through the transformer, heating its resistance more. It also slightly raises the average voltage (because of those filled in valleys), making the motor draw more current, which heats the transformer even worse. The motor obviously does not require filtered DC voltage, but runs just fine on the rectified voltage wave, smoothing the current some, with its own inductance.

How's that?