Jabco Bilge Pump Polarity

[A la carte]

Had to replace 12V DC motor on my Jabco 36000 series bilge pump. Both wires from pump are black and I was concerned about polarity. While trying to determine polarity, I ran the pump briefly switching polarity to see which way the pump would run. Figured I'd hook it up whichever polarity produced correct motor rotation. The DC motor rotates the correct direction regardless of polarity. Not being an electrical genius, I don't understand how this can be the case. Does Jabco somehow design their motors to run the correct direction regardless of polarity or am I misunderstanding how a DC motor works?

[s/v Jedi]

Originally Posted by A la carte

Had to replace 12V DC motor on my Jabco 36000 series bilge pump. Both wires from pump are black and I was concerned about polarity. While trying to determine polarity, I ran the pump briefly switching polarity to see which way the pump would run. Figured I'd hook it up whichever polarity produced correct motor rotation. The DC motor rotates the correct direction regardless of polarity. Not being an electrical genius, I don't understand how this can be the case. Does Jabco somehow design their motors to run the correct direction regardless of polarity or am I misunderstanding how a DC motor works?

Did you check the manual or installation instructions?

[GordMay]

That they didn’t label the wires, implies that Jabsco doesn’t care about polarity.
Which ever way the motor rotates [CW or CCW], the crank arm will still go up and down, and the direction the water flows, is determined by the valves, not the motor.
Install the fuse & switch[es] in whichever lead you connect to the positive battery supply.
➥ https://www.pumpagents.com/pdf/Jabsc...36600-0000.pdf

[ggray]

Gord is right that it doesn't matter to a diaphragm pump which way the motor spins, but the OP said it spins the same direction regardless of which way it is wired.

That seems odd to me, but I'm aware of my electrical limitations!

Can anyone comment on this?

[GordMay]

Originally Posted by ggray

... the OP said it spins the same direction regardless of which way it is wired.
That seems odd to me,
Can anyone comment on this?

I suspect the OP is wrong.
The motor changes rotational direction, with polarity, but the piston still goes up & down.

[SailingHarmonie]

Originally Posted by GordMay

I suspect the OP is wrong.
The motor changes rotational direction, with polarity, but the piston still goes up & down.

When you reverse polarity it no longer goes up and down, it goes down and up.

[AKA-None]

Originally Posted by SailingHarmonie

When you reverse polarity it no longer goes up and down, it goes down and up.

<sigh>

[SailingHarmonie]

Originally Posted by AKA-None

<sigh>

Sorry, I could not resist... Banish me to the joke thread...