[H]ard Question ....

[rgMekanic]

hokay... I'm upgrading my old Koolance PC2 case.

There is a control board in the top that provides the LCD display, works as a temp based fan controller for the rad fans, and controls the (stock) pump.

I'm still using the board for everything but the pump, which I have changed to an MCP655.

All is well, except the fact the onboard transformer has developed a buzz. My theory is the fact that there is no load on the pump circuit.

Using Ohm's law, knowing that it is a 12v pump @ 3w should be 15 ohm, but I'm not getting any reading on my meter from the pump leads

Question, can I solder a 15ohm resistor into the old pump lead to put a load on the pump circuit of the board? If yes, what wattage rating on the resistor, as I don't play with them much I have no idea.

Thanks!

~Rich

 

[BinarySynapse]

If you could, you'd need at least a 3w resistor. But you're replacing an inductive load with a resistive load, and I'm not sure how that affects things.

 

[rgMekanic]

Just got a reading on my meter, think I need new leads, pumps are 16.3 ohms.

 

[BinarySynapse]

Just got a reading on my meter, think I need new leads, pumps are 16.3 ohms.

That's most likely right. A DC motor is an inductor, and would shift the current out of phase with the voltage (i.e. current is at a max when voltage is at a minimum.. or when the brushes break contact with the pads), so total power dissipated would be less then a resistive load for a given readings. .

 

[rgMekanic]

That's most likely right. A DC motor is an inductor, and would shift the current out of phase with the voltage (i.e. current is at a max when voltage is at a minimum.. or when the brushes break contact with the pads), so total power dissipated would be less then a resistive load for a given readings. .

Right, and since I can't get an ohm reading with them running .. I wonder if I should hook them back up and get the RLA and do the math from there.

But were still dealing with the inductive vs. resistive and I don't know what that will do to the situation.

Just know the transformer is loud and it is a discontinued board that I DO NOT want to cook haha.