Electrical pump affecting other devices

[crgarcia]

I had a swimming pool pump (1) and next to it a device (2) that measures the Ph and other stuffs with smaller pumps to add chlorine, etc.
Both devices where connected to sockets next to each other, with the same line from mains using Wago connectors

Diagram:


The pump broke, and the company changed it for a new one. The new one works fine, but now the slow-blown fuse (3) of the measurement device breaks all the time.
The company that installed the pump is saying that the installation is probably defective, and the problem cannot be the pump, but when i connect the pump to a different wire (same phase, just longer wire) then everything works fine

Diagram:


What could be the issue?
Is there any way I could measure the noise (or whatever) with an oscilloscope and differential probes?

Thank you very much!

[thm_w]

You could measure some of the noise with a differential probe yeah. Maybe switch on and switch off will be the worst.

Its possible the pump is generating a high voltage, and there is a MOV in device 2 that is clamping that and blowing the fuse. But without seeing what device 2 is or how its connected its hard to say.

Any model numbers for the pump or device?

[Benta]

Unlikely that the pump would generate spikes that would blow a fuse.
A more likely scenario is that your controller [3] is badly designed to withstand "brownouts".
Your pump seems to be a single-phase, cap-run induction motor.
Those can draw up to 6...8 times nominal current during starting, and if your 230 V supply isn't "stiff" enough, you'll have a brownout condition where the line voltage drops.
Your supplying the pump through a longer cable away from the controller supports that scenario.
Any chance of connecting the pump to another mains phase?
In any case, check all the connections, also at the house. A corroded joint somewhere can make a lot of trouble.

[coppercone2]

i would be suspicious of the pump that is causing strange things to happen it might mean bad high voltage electrical connections


it sounds like you should have a electrician check out the run. i know someone that almost got killed working on some stupid pool pump with bad wiring

I don't recall exactly but something about wet concrete being unusually conductive. maybe the pool chemicals too.

if you have a brown out the power supply will draw more current an blow a fuse, the best tool for shady pumps is a graphing meter like a fluke 289, then you can record line voltage over time while you are not near the thing when its powered up