can any one help with this project, 24vac

[vipercat64]

hi all
i'm new here

i hive two waterpumps in my computer system that runs from Koolance control
model that use the 12DC power from pc PSU, this control unit is dead.

so i need to make 24VAC power supply.
the waterpumps need 24vac to run.

went to radio shack and pickup power transformer rated at 120vac/ out-25.2 volt ac, 450ma this transformer gets to hot.

what do need to do?
a circuit for 24vac output from 120vac or make a circuit that run from 12DC conver to 24vac.

please help..

 

[MikeMl]

Sounds to me that you just need a 24V transformer with a higher secondary current rating. 0.45A@24V is only 10VA. I guessing you need at least 50VA (2A) rating.

Do you know what the rating of the pumps are?

Can you measure the current draw of the pump?

 

[vipercat64]

thanks for you reply

i think they are rating at 2A or more possable at 4.5A
i did one test with a transformer rate 120vac/ 50va, but when i put the pumps on it
the 24.4va drop down to 8.99va, this transformer its about 1A or less.

i think i need a transformer rate at 3A to 5A 50va.

 

[MikeMl]

The VA rating of a transformer is obtained by multiplying its secondary voltage by its secondary current rating, so if you know its current rating VA=Vsec×Isec.

If you know its VA rating and Vsec, then Isec=VA/Vsec

Sounds to me that each pump requires 4.5A, so two require 9A, so the required VA rating of the transformer is at least either 24Vac@9A or 24Vac@216VA.

 

[vipercat64]

look at pics PCA baord.

this power control panel is "" 12VDC CONVER 24VAC OUTPUT

**broken link removed**