Intex Inflatable Spa - Pump Problems

[mmartell]

Re: Intex Inflatable Spa - Pump Problems

Thanks for that bud! Only two wires so no speed control.

Took some measurements at the unit. The voltage at the pump (with or without the pump) is 13.5v ac. The current draw on the motor is 5.25 amps.

If I rectify 13.5v doesn't that come out to a fair bit less than the 12v necessary ?

[goontron]

Re: Intex Inflatable Spa - Pump Problems

^Personally i would just build the bridge and install the pump. You gotta figure, what "12v" are they referencing? the 13v8/14v2 charge power of a vehicle's 12v system? That's what i assume....

[mmartell]

Re: Intex Inflatable Spa - Pump Problems

Ok so I should have thought more about this - when we rectify the incoming ac in a power supply the result is roughly 170vdc. So if I rectify 13.25vac I should have about 18.75vdc minus any drops through diodes (1 or 2v?) Does that sound right ?

Isn't that a little too much to feed the pump ? What's the best way to reduce it ?

[stj]

Re: Intex Inflatable Spa - Pump Problems

at 5A+, better to put a £10 switching psu in from china.
8-10A at 12v

[stj]

Re: Intex Inflatable Spa - Pump Problems

or an old pc psu - dont forget to put the results in the ghetto mod thread.

[mmartell]

Re: Intex Inflatable Spa - Pump Problems

Lmao

[budm]

Re: Intex Inflatable Spa - Pump Problems

Thanks for that bud! Only two wires so no speed control.

Took some measurements at the unit. The voltage at the pump (with or without the pump) is 13.5v ac. The current draw on the motor is 5.25 amps.

If I rectify 13.5v doesn't that come out to a fair bit less than the 12v necessary ?

Is that the current draw of the new pump or the old pump? What DCV applied to the new motor? 5.25A, that is more than the twice current rating of the motor with 12VDC applied.

[mmartell]

Re: Intex Inflatable Spa - Pump Problems

The current draw was measured on the old pump with 13.5vac applied. The new pump has only been tested with a 12v battery, no current draw test has been done on it yet.

[goontron]

Re: Intex Inflatable Spa - Pump Problems

Just whack it in. Chances are if the pump has died the vinyl sheeting isn't far off...

[mmartell]

Re: Intex Inflatable Spa - Pump Problems

Do I have to use 3A diodes to make a bridge ??

[stj]

Re: Intex Inflatable Spa - Pump Problems

use a rectifier with a metal base for those currents.
it will make it simpler anyway, because they have spade terminals.

[mmartell]

Re: Intex Inflatable Spa - Pump Problems

Sounds good but what is the significance of the spade terminals ?

[stj]

Re: Intex Inflatable Spa - Pump Problems

makes it easy to attach the wires

[mmartell]

Re: Intex Inflatable Spa - Pump Problems

I considered that but I thought there might be something deeper lmao

[mmartell]

Re: Intex Inflatable Spa - Pump Problems

So can I get away with a rectifier and an LM7812 ?

[stj]

Re: Intex Inflatable Spa - Pump Problems

no.
read the datasheet - a 7812 is rated for 1A and then only with a heatsink the size of a brick!

[budm]

Re: Intex Inflatable Spa - Pump Problems

Can you get 12V 5A switching power supply brick from recycle place, if there is one close by?

[mmartell]

Re: Intex Inflatable Spa - Pump Problems

Bud I probably could and would be the easiest way to do it I would just learn less What device would use that type of supply ?

Stj I should have said the LM7812A I think it's rated for 5A.

[stj]

Re: Intex Inflatable Spa - Pump Problems

old tv's & monitors with ccfl backlights used big psu's

[budm]

Re: Intex Inflatable Spa - Pump Problems

Bud I probably could and would be the easiest way to do it I would just learn less What device would use that type of supply ?

Stj I should have said the LM7812A I think it's rated for 5A.

It will dissipate about 12 Watts (Vdrops on the IC: 18V -12V = 6Vdrops; 6V x 2A load = 12 Watts) of power at 2A load so good heatsink will be required.