Transformer Issue

[Garni1]

Hi, wondered if anyone could help with this. We have purchased a 12vdc caravan pump to use in our food trailer. They are designed to run off a leisure battery but we have a generator and would like to run it off a standard 3 pin 240v plug.

What would be the best transformer to use?

Attached is a picture of the pump.

Thanks!

 

[DPG]

You will need a power supply that outputs 12V DC and is capable of 4.5 Amps or more.

Make sure you get polarity correct when you connect it up, and use cable capable of handling the current.

 

[telectrix]

you need a 12V DC PSU as he^^^^^ says, a 5A one should do. cut the d.c. pug off and hard wire to pump.

View: https://www.amazon.co.uk/100-240V-Regulated-Switching-Amplifier-Accessories/dp/B01G9YS4NU?ref_=fsclp_pl_dp_10

 

[Lucien Nunes]

The thing in your picture is an electronic lighting 'transformer' that is designed specifically to power 12V lamps, not act as a general 12V power supply, and may not have a DC output.

As above, you want a DC power supply unit; I would be a bit more generous with the current rating as you do not want the PSU shutting down on the startup surge of the pump motor (which would normally be handled by the 'van battery). You might like to try something of this ilk:
12V 7.5A PSU from CPC

I have long experience of the Shurflo pumps - I have two of the larger units on my boat that run in tandem - and they are good little workhorses. I service them every 5 years and they are now over 20 years old. Their predecessor served for ten years before being re-purposed and is still going strong.

 

[Garni1]

you need a 12V DC PSU as he^^^^^ says, a 5A one should do. cut the d.c. pug off and hard wire to pump.

View: https://www.amazon.co.uk/100-240V-Regulated-Switching-Amplifier-Accessories/dp/B01G9YS4NU?ref_=fsclp_pl_dp_10

Hi mate thanks for the advice, just to clarify, are we cutting the connection off the amazon product and connecting to red and black wires on the pump?
Cheers

 

[DPG]

Hi mate thanks for the advice, just to clarify, are we cutting the connection off the amazon product and connecting to red and black wires on the pump?
Cheers

Read Lucien's post first.

 

[telectrix]

Hi mate thanks for the advice, just to clarify, are we cutting the connection off the amazon product and connecting to red and black wires on the pump?
Cheers

yep, but as Lucien says, best to have a PSU that's more than adequate rather than one that's under rated. you'll need a multimeter ( a cheap one will do ) to check which wire are poz. and neg.

 

[Garni1]

you need a 12V DC PSU as he^^^^^ says, a 5A one should do. cut the d.c. pug off and hard wire to pump.

View: https://www.amazon.co.uk/100-240V-Regulated-Switching-Amplifier-Accessories/dp/B01G9YS4NU?ref_=fsclp_pl_dp_10

Thanks for this. Ordered it and it's coming today. When I strip the wires and attach them to the red and black on the pump, how do I know which is which?

Cheers

 

[telectrix]

you'll need a multimeter. generally the centre contact in the plug is +ve (red). but the colours of the PSU cable could be anything.

 

[DPG]

A lot of power supplies these days use shielded cable, where the negative is formed by bare wires surrounding the central core. The central core is generally insulated in white material.

As Tel says though, a multimeter will confirm correct polarity.

 

[Garni1]

A lot of power supplies these days use shielded cable, where the negative is formed by bare wires surrounding the central core. The central core is generally insulated in white material.

As Tel says though, a multimeter will confirm correct polarity.

Thanks I'll grab a multimeter.
[automerge]1596021549[/automerge]

you'll need a multimeter. generally the centre contact in the plug is +ve (red). but the colours of the PSU cable could be anything.

Thanks I'll get one

 

[Lucien Nunes]

The last time I bought these they did indeed have a coaxial cable, centre core positive. The correct way to terminate it is to form the outer conductor up into a neat cable and sleeve it, then sleeve overall for 1/4" either side of the end of the original cable sheath (adhesive heatshrink is ideal) so that the point at which the outer conductor emerges and goes into its own sleeving is covered.

 

[Garni1]

The last time I bought these they did indeed have a coaxial cable, centre core positive. The correct way to terminate it is to form the outer conductor up into a neat cable and sleeve it, then sleeve overall for 1/4" either side of the end of the original cable sheath (adhesive heatshrink is ideal) so that the point at which the outer conductor emerges and goes into its own sleeving is covered.

Thanks for the help. This worked. All sorted. Great place and people to get sorted from. Really appreciate it! Cheers.