Static Noise in Audio during washing machine operation

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thatsashok

thatsashok

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I have a question that has been bugging me every weekend while washing clothes with music On and being a mechanical engineer my knowledge has been limited to analyse the problem (momentary discomfort) at hand and expecting that the electrical engineers in the forum will help me understand

I notice that when the washing machine is working there is static noise produced in the PC audio speakers & this noise occurs momentarily and exactly in sync with the time when the motor of the washing machine changes direction of rotation during the tumble wash.

Another observation I have is that the static noise (volume/sound intensity) does not increase or decrease with the change in the volume output of the 2.1 Audio system via Knob or increasing the PC volume.

My questions are
  • Why should a noise be produced in my Audio speakers when its audio input (Aux, no DAC) via PC are appliances that work on DC ? I understand that both PC and Speakers draw power from same home AC circuit
  • Is this phenomena normal ? the building I live in is Old (electrical wiring and safety features wise) if that help
I may be wrong in assuming some of the things, but would like to understand this phenomena in details technically and learn more about it

Looking eagerly for the responses
 
Do you have two circuits in the house or is everything on one circuit ?

Usually there is a lighting circuit and a heating circuit.

Boilers, washing machines with the 15A plugs will be on the heating circuit.

Everything else is on the lighting circuit.

Two different networks. Surges on one do not cause interference with the other.
 
blr_p said:
Do you have two circuits in the house or is everything on one circuit ?

Usually there is a lighting circuit and a heating circuit.

Boilers, washing machines with the 15A plugs will be on the heating circuit.

Everything else is on the lighting circuit.

Two different networks. Surges on one do not cause interference with the other.
Click to expand...

That's assuming you have 3 phase power. Most small flats have single phase power.
 
Chaos said:
That's assuming you have 3 phase power. Most small flats have single phase power.
Click to expand...
Not 3 phase. We have single phase in the house. There are two circuits. Heating & lighting for each floor. I thought this was a standard setup here.

Flats i'm not sure about.

Having said that i do have a 3 phase cable coming in. One phase powers the ground floor, the second the top and the last is free.

One phase per floor.
 
Chaos said:
Check the grounding in your house. It is obviously screwed up.
Click to expand...

On it now. Thanks for the input

blr_p said:
Do you have two circuits in the house or is everything on one circuit ?

Usually there is a lighting circuit and a heating circuit.

Boilers, washing machines with the 15A plugs will be on the heating circuit.

Everything else is on the lighting circuit.

Two different networks. Surges on one do not cause interference with the other.
Click to expand...

Washing machine is connected to the high amperage wall outlet socket. I think its 15A as you pointed out.
Speakers were on the normal outlet through a Belkin spike buster

blr_p said:
Not 3 phase. We have single phase in the house. There are two circuits. Heating & lighting for each floor. I thought this was a standard setup here.

Flats i'm not sure about.

Having said that i do have a 3 phase cable coming in. One phase powers the ground floor, the second the top and the last is free.

One phase per floor.
Click to expand...

Single phase
 
1. Check Earthing as @Chaos suggested. If that solves issue Well and good.
2. Call an electrician and check for any loose contacts in Socket or Connector/ Wires inside the connector where machine is connected.
3. Which model of washing machine is it? You may need to call service for the below.
a. Some Solid state electronics is injecting frequencies to you AC power, May be a bust cab or a slightly arcing SSE.
b. Worst case scenario: How old is your machine? If it is old then It's the Motor and brushes, You may want to replace the brushes. Cause they are causing a slight arcing when operating which is causing the noise.
Hope that helps... :)
 
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manucitc said:
You should just make new grounding for your house, contact local electrician, he will just dig up hole near your wall and now days there's chemical available for so no need to use salt and coal...
Click to expand...
You mean the problem may not be with the entire cabling running inside the house, but only the earthing pit?

Chaos said:
Means the power sockets are not grounded correctly. Your washing machine is polluting your electrical ground. Speak to an electrician.
Click to expand...
Still not clear. The three pin plug/socket has one earth wire, one phase wire, one neutral.
Why would my equipment (washing machine or anything else) even utilize the earth wire for closing its circuit? It is supposed to use only the phase and neutral.

So any disturbance or harmonics created by washing machine would anyway be transmitted to another equipment if it shares the same phase and neutral cable. How does the earthing come into picture?
 
If its earthing issue means, why its occurring momentarily? It should occur always right? Looks like surge issue, since it occurs during change of direction motor direction.
 
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Chaos said:
Please read this. Gives the reasons for audio disturbances due to flawed grounding.

Staying Well Grounded | Analog Devices

Grounding is an issue for all analog designs, and it’s a fact that proper implementation is no less essential in PCB-based circuits. That’s the focus here.
www.analog.com www.analog.com
Click to expand...
"For linear systems, the ground is the reference against which we base our signal. Unfortunately, it has also become the return path for the power-supply current in unipolar supply systems. "

Does this mean that the neutral and earth in house circuits are at same potential and connected to each other?
 
ssslayer said:
"For linear systems, the ground is the reference against which we base our signal. Unfortunately, it has also become the return path for the power-supply current in unipolar supply systems. "

Does this mean that the neutral and earth in house circuits are at same potential and connected to each other?
Click to expand...

Yes and no! Unipolar systems have only a neutral and live. Bipolar has neutral, live and ground. Many houses in India have screwed up grounding causing neutral and ground to be connected to each other causing trouble.
 
Chaos said:
Yes and no! Unipolar systems have only a neutral and live. Bipolar has neutral, live and ground. Many houses in India have screwed up grounding causing neutral and ground to be connected to each other causing trouble.
Click to expand...
That is a major screw up with wiring if true.

I interpreted unipolar to mean has only two sockets on the plug. So earth & neutral are shared.

The washing machine has three plugs on the socket.

It appears there is no separation of circuits in this guys house for interference on the 15A socket to transmit over to the lighting. Which strikes as a bit odd

Can the OP check his fusebox and observe the ratings on the fuses.

There will be fuses that are more than 15A and 10A ones or all of them the same number in which case what is it ?
 
ssslayer said:
Does this mean that the neutral and earth in house circuits are at same potential and connected to each other?
Click to expand...

Yes. Neutral wire must be grounded in an electric distribution system. This is important for safety and is mandated by the govt.

Seee section 41 of Central Electric Authority's Measures relating to Safety and Electric Supply:


There may be a few volts difference between ground and neutral because the ground wire doesn't carry current.
 
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dpandey said:
Yes. Neutral wire must be grounded in an electric distribution system. This is important for safety and is mandated by the govt.

Seee section 41 of Central Electric Authority's Measures relating to Safety and Electric Supply:


There may be a few volts difference between ground and neutral because the ground wire doesn't carry current.
Click to expand...

Chaos said:
Yes and no! Unipolar systems have only a neutral and live. Bipolar has neutral, live and ground. Many houses in India have screwed up grounding causing neutral and ground to be connected to each other causing trouble.
Click to expand...

Now I am confused, CEA mandates Earth and Neutral connected, while Chaos says it shouldn't be.
 

Electrical Safety Earthing | Electrical India Magazine on Power & Electrical products, Renewable Energy, Transformers, Switchgear & Cables

www.electricalindia.in www.electricalindia.in

One can read about the different types of earthing systems and how they are different from each other in this article.
It says that in India, the TN-S system of earthing is prevalent which means that Neutral and Earth are seperate and run seperately on overhead cables but that does not seem to be true. In fact, by the different definitions, it seems the TT system of earthing is the most prevalent in India with both supply and home equipment being directly connected to earth at their respective places.
 
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