Static Noise in Audio during washing machine operation


thatsashok

Active Member
Adept
Feb 7, 2011
620
30
43
Nashik / AP
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
 

manucitc

Well-Known Member
Disciple
Aug 8, 2012
714
231
82
What does that mean?
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...
 

blr_p

Well-Known Member
Veteran
Apr 11, 2007
6,102
1,295
301
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.
 

Chaos

Well-Known Member
Veteran
Jan 29, 2005
9,087
902
252
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.
That's assuming you have 3 phase power. Most small flats have single phase power.
 

blr_p

Well-Known Member
Veteran
Apr 11, 2007
6,102
1,295
301
That's assuming you have 3 phase power. Most small flats have single phase power.
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.
 

thatsashok

Active Member
Adept
Feb 7, 2011
620
30
43
Nashik / AP
Check the grounding in your house. It is obviously screwed up.
On it now. Thanks for the input

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.
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

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.
Single phase
 

Lozil

Well-Known Member
Adept
Feb 11, 2006
216
16
87
Bangalore
lozil.blogspot.com
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... :)
 
  • Like
Reactions: blr_p

ssslayer

Well-Known Member
Adept
Jun 30, 2006
435
137
131
Pune
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...
You mean the problem may not be with the entire cabling running inside the house, but only the earthing pit?

Means the power sockets are not grounded correctly. Your washing machine is polluting your electrical ground. Speak to an electrician.
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?
 

smnrock

Well-Known Member
Veteran
Apr 9, 2009
1,218
227
153
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.
 
  • Like
Reactions: ssslayer

Chaos

Well-Known Member
Veteran
Jan 29, 2005
9,087
902
252
Please read this. Gives the reasons for audio disturbances due to flawed grounding.

 

ssslayer

Well-Known Member
Adept
Jun 30, 2006
435
137
131
Pune
Please read this. Gives the reasons for audio disturbances due to flawed grounding.

"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?
 

Chaos

Well-Known Member
Veteran
Jan 29, 2005
9,087
902
252
"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?
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.
 

blr_p

Well-Known Member
Veteran
Apr 11, 2007
6,102
1,295
301
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.
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 ?
 

dpandey

Well-Known Member
Adept
Jul 11, 2010
269
180
81
Bangalore
Does this mean that the neutral and earth in house circuits are at same potential and connected to each other?
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.
 
Last edited:
  • Like
Reactions: ssslayer

ssslayer

Well-Known Member
Adept
Jun 30, 2006
435
137
131
Pune
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.
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.
Now I am confused, CEA mandates Earth and Neutral connected, while Chaos says it shouldn't be.
 

rdst_1

Well-Known Member
Veteran
May 10, 2009
2,525
1,120
253
32

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.