Connecting a pump to wall socket using a transformer

Hi!
I’d like to connect following components:

  1. From the wall socket
  2. … to a cable
  3. … to a pressure switch
  4. … to a transformer
  5. Use the outer wires on the transformer to get 24V (2x12V) to the pump

Question is, how? I’ve no idea how to actually connect these components. I’m a complete and utter noob and I’ve no experience whatsoever with these things.

I’ve made a picture of the components.

First off, the cable is unearthed (should it be?) but there are only two connects (in/out) to the pressure switch, where should the earthed wire go?

Two wires to the in/out on the pressure switch to the transformer - does it matter which one?

From the transformer to the pump, should I put those blue wires together in the same place? Does it matter which ones I connect to what on the pump (+ / -).

I’d appreciate some help!

P.S I dont want to get fried.

Connects.pdf (131 KB)

Post a link to the pressure switch.
If you don't get this right, you'll start a fire or kill yourself. Best to get hands on advice from someone who understands AC circuitry.

jremington:
If you don't get this right, you'll start a fire or kill yourself.

Or more tragically, someone else.

jremington:
Post a link to the pressure switch.
If you don't get this right, you'll start a fire or kill yourself. Best to get hands on advice from someone who understands AC circuitry.

Don't worry, I won't do anything unless I'm sure it's safe.

The link doesn't say much really

But I assume it's a standard 4-pin (2x in, 2x out) construction.

It ought to look like:

The link doesn't tell me anything.

unless I'm sure it's safe.

How will you know to be sure?

jremington:
The link doesn’t tell me anything.
How will you know to be sure?

Well, it’s just a pressure switch like any other really…

I can’t be 100% sure but I’ll read up on it, asking on forums etc

Got any ideas?

Use your multimeter on the "continuity" setting to double check which connections on the pressure switch go where.

LHS89:
Well, it's just a pressure switch like any other really..

I can't be 100% sure but I'll read up on it, asking on forums etc

Got any ideas?

The issue is not that it's a pressure switch. It's that you intend to play around with 230VAC and you don't know much about electrical safety.

The pressure switch is connected wrong to the primary of the transformer.
You have an IN connected to primary-1, and the Out connected to Primary-2.

The switch should be in SERIES. not ACROSS the primary.
The power wires should go to the two INs.
The transformer primary wires should go to the two OUTs.
(duh.)
The way you have it wired, the switch would SHORT the two power wires if the pressure was below the setpoint. (assuming the switch is N.C. and OPENS on overpressure.

I've no experience whatsoever with these things.

Then you shouldn't be doing it until you learn the basics, like the difference between and open and a short.

totally agree.

These types of pumps often come with an approved psu with a plug suitable for connecting to the mains.

If you want to modify them you have to be a competent or approved person.

I suggest you consider a power tail or similar which are approved and allow you to connect safely to the mains.

By power tail i mean available mains switching units which can be safely controlled from an arduino etc , available from the like of maplins in the UK

Everyone except the OP can look at the components posted and draw up a schematic for it in 5 minutes (including the pump connection , which is obvious by the way) but frankly I don't want any part of putting a ticking time bomb in the OP's hands. I'm done.

Thanks for answers!

raschemmel:
The pressure switch is connected wrong to the primary of the transformer.
You have an IN connected to primary-1, and the Out connected to Primary-2.

The switch should be in SERIES. not ACROSS the primary.
The power wires should go to the two INs.
The transformer primary wires should go to the two OUTs.
(duh.)
The way you have it wired, the switch would SHORT the two power wires if the pressure was below the setpoint. (assuming the switch is N.C. and OPENS on overpressure.

Then you shouldn't be doing it until you learn the basics, like the difference between and open and a short.

I admit that I kind of guessed the "schematics" of the pressure switch. But I think I've got that problem fixed, there are good instructions in the manual and with your supplementary answer I've got it covered!

Boardburner2:
totally agree.

These types of pumps often come with an approved psu with a plug suitable for connecting to the mains.

If you want to modify them you have to be a competent or approved person.

I suggest you consider a power tail or similar which are approved and allow you to connect safely to the mains.

By power tail i mean available mains switching units which can be safely controlled from an arduino etc , available from the like of maplins in the UK

That would be easier but I need to have a pressure switch when connecting the pump to a hydraulic accumulator and it's not realistic to manually activate it everytime the pressure drops.

raschemmel:
Everyone except the OP can look at the components posted and draw up a schematic for it in 5 minutes (including the pump connection , which is obvious by the way) but frankly I don't want any part of putting a ticking time bomb in the OP's hands. I'm done.

I'm here to learn! It's not obvious for me and frankly "it's obvious" doesn't help me much! In any case, I appreciate your answers and concerns.

Can you point me to a site or book which is a must read?

Frankly, we would much rather that you found an experienced, presumably qualified person such as an electrician who could work with you and at the very minimum, observe in person what you are doing at each step.

Paul__B:
Frankly, we would much rather that you found an experienced, presumably qualified person such as an electrician who could work with you and at the very minimum, observe in person what you are doing at each step.

Ok. Still doesn't help me much.

Ok. Still doesn't help me much.

What's to help ? Everything you need to know about the wiring has already been explained. If you haven't got it running yet then either you can't read or you can't add.

What exactly , do you still NOT understand about the wiring ?

Have you thought of using Google to answer your questions ?

LHS89:
Ok. Still doesn't help me much.

Saving you from death, imprisonment and/or litigation isn't helpful? Okay.

Saving you from death, imprisonment and/or litigation isn't helpful? Okay.

Ours is a thankless job....

aarg:
Saving you from death, imprisonment and/or litigation isn't helpful? Okay.

It's hard enough to give advice to people you THINK are qualified.

I used to do appliance repair. I was in a parts store and was talking to a man that was the head of maintenance of a large high rise. His brother was having trouble with a range and he wasn't familiar with it. I knew the range well. The wires used to burn off the terminals of the oven lock switch. They were an absolute nightmare to get at though. I told him the easiest way to check was to go to the back of the range. There were two heavily insulated white wires coming down from the top. One on the left side of the range, the second on the right side. Check for continuity. If none, jump them out and see if the range works.

Next time I see him he starts yelling at me. I asked him what he did. "Just what you told me to do. I jumped the white and black wires on the ceramic block."

Even if I had told him to do that just for fun, any one with a clue knows you don't jump out a light bulb. And this is a guy that should have known better. Makes me shudder that people like this are in a position to harm other people with their pseudo knowledge.

LHS89:
Thanks for answers!

That would be easier but I need to have a pressure switch when connecting the pump to a hydraulic accumulator and it's not realistic to manually activate it everytime the pressure drops.

You do not need to the powertail has a 5 or 12 volt signal input that is protected.

Use the pressure sensor with a battery or wall wart to activate it.

The powertail correctly plugged in to approved outlets does all the protection for you

outofoptions:
It's hard enough to give advice to people you THINK are qualified.

Just as hard to buy spares from as well.

Recently had a microwave blow due to a power surge.

Needed a T10A fuse.

3 on line suppliers , and a microwave repair place who all KNEW what i was talking about and sold me the fuses.

Microscope on the end cap showed none were T rated , and all blew.

Despite the packet saying otherwise.