| T O P I C R E V I E W |
| DINGLEs |
Posted - Feb 06 2009 : 7:38:06 PM
i have a current problem i need to transform 120vac to 24vdc at 8 amps (minimum) how can i do this? i know i will need a Rectifier of some sorts. but i cant find a 24v transformer that has enough amps to drive the motor.
can anyone clue me in on how i could do this with a 24vac 40va transformer simply or is there an inexpensive solution already made up?
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| 3 L A T E S T R E P L I E S (Newest First) |
| audioguru |
Posted - Feb 07 2009 : 10:06:02 AM
The 40VA transformer is too small to power an 8A motor. The transformer will be severely overloaded and might catch on fire.
24VAC x 1.414= 40V peak. A 40VA transformer will be at its limit when the DC current is 40VA/40VDC= 1.0A. |
| DINGLEs |
Posted - Feb 07 2009 : 12:59:32 AM
OK.. so what your saying is... say i use a standard 24volt 40va transformer. what rectifier would i need and is it available at say. radio shack? or need i order it online. basically what im looking for is to power a drive motor for a gun range the guy said that it is a dc motor and it draws 8 amps he also said it can handle 40 volts with no problem so im assuming its a 6-90vdc motor. it has to travel back and forth 50 ft out and back.
so what i want to do is make a power supply out of a 40va transformer if possible (to keep cost down and easy fix)
what can i do to make it so that it can handle a this large demand?
they need it to run on a standard M. ON/OFF/M. on toggle switch 2 pole (that i have)
so basically i just need to make a power supply :)
if you can help with a wireing diagram and a parts list that would be AWSOME.
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| audioguru |
Posted - Feb 06 2009 : 9:02:03 PM
A 24VAC transformer makes 32VDC when the AC is rectified and filtered.
An 18VAC transformer makes 23.5VDC when the AC is rectified and filtered.
A 24VAC/40VA transformer is a little one with a current of only 40/24= 1.7A.
You need 8ADC, not 8AAC so the transformer must be 18VAC/11.3A or 204VA minimum.
A DC motor uses maybe 10 times its average current to start or when it is stalled. |
