Continue to Site

Welcome to our site!

Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

  • Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

How to put back wires in the rotary switch(for speed adjustment) of food mixer

Status
Not open for further replies.

deep

New Member
I was trying to repair my domestic (Sumeet) food mixer(it uses a universal motor). When I opened the back of the rotary switch, which is used for varying the speed, the wires came out before I had an opportunity to notice where they were connected. Please help me put them back......
There are total 4 wires going into the switch.One is the red wire coming from the supply. The other three are orange, blue and yellow and goes to the stator windings of the universal motor.When we turn the rotary switch,one of these wires gets connected to the red wire coming from the supply at a time.
The yellow wire has 2 pins connected to it, one directly and the other, through a diode. Thus, there are 4 positions for the rotary switch,i.e, when the current flows through the orange, blue, or yellow wire directly or through the diode and then through the yellow wire. The rotary switch has various speeds marked on it (0,I,II & III). I need to find out, to which speed the connection to a wire corresponds.
The motor looks somewhat like this:
www.globe-usa.com/images/mtrassytom2.gif
As you can see, there are 2 stator coil windings to provide the field. The blue and orange wires split into two on approaching the motor and one of them gets connected to each stator winding, thus connecting the stator coils in parallel, whereas the yellow wire is connected only to one coil- the other coil is connected to the neutral(black) wire from the supply.
Thus, the connections to each stator winding are as follows:
1) yellow, orange, blue
2) neutral wire, orange, blue.
In addition, each of these windings are connected to the rotor through one of the brushes.

Thus,when the yellow wire is connected to the supply, the current flows through the first stator winding, then through some wires on the rotor, then through the second stator winding and back to the supply through the neutral wire connected to it. When the yellow wire is connected through the diode, the the rms voltage supplied would reduce to half, as current flows only during one half cycle.
However, when the orange or blue wires are connected, current can flow through the second winding and go to the neutral wire directly, in addition to the path mentioned for the current through the yellow wire.
How would this affect the speed of the motor? Morover, I can find no difference in the circuits formed by the blue and orange wires ( maybe, the difference lies in a portion of the motor, which is not visible externally.)
Above all, to which of the wires would the zero speed correspond to? This is the greatest puzzle for me.
If you can figure it out, please post the combination of wires and speeds.
In other words, match the following:
0 a)yellow wire through diode
I b) yellow wire directly
II c)blue wire
III d)orange wire
 
Check which terminal on the switch is common to discern where to start applying the supply wire.
Connect a 100W light bulb in series with the appliance and start trying all permutations until speeds corresponds to selection.
Or ask a tecnician at an appliance service center, they must have the schematic.
 
Dear Externet
The problem is that I have to put back everything such that when we take the mixer to the service centre, the technicians there shouldn't know that someone else has tried to repair it. If they come to know it, they say-"Well then, take it to the person who worked on it."
Actually, I never hoped to repair it. I had learned about DC motor at school and just wanted to see how motors actually look, but now, you see i am stuck up with this rotary switch.
This is the first time I work on some electrical appliance. So, I am not confident enough to cut any wire's insulation to connect a bulb, or pass electricity.
Can you get any clue from the description I have given earlier?

If there is someone out there who uses a Sumeet mixer, please tell me the order in which the coloured wires come out of the switch. I would be greatly obliged.
 
Hi.
You do not have to cut any wire insulation to connect a bulb in series to the appliance. You do it at its wall plug or to a extension cord on it, or to plain wires hooked to it, with lot of care to not get shocked. Keep it unplugged while you reconnect trying permutations.
 
Dear Sir,
What's the model of the diode around rotary switch? Is that 1N4001? or some thing else?
My Sumeet mixie's diode in the back of rotary switch literally fried. I need to replace that diode.
Thank you.
 
I was trying to repair my domestic (Sumeet) food mixer(it uses a universal motor). When I opened the back of the rotary switch, which is used for varying the speed, the wires came out before I had an opportunity to notice where they were connected. Please help me put them back......
There are total 4 wires going into the switch.One is the red wire coming from the supply. The other three are orange, blue and yellow and goes to the stator windings of the universal motor.When we turn the rotary switch,one of these wires gets connected to the red wire coming from the supply at a time.
The yellow wire has 2 pins connected to it, one directly and the other, through a diode. Thus, there are 4 positions for the rotary switch,i.e, when the current flows through the orange, blue, or yellow wire directly or through the diode and then through the yellow wire. The rotary switch has various speeds marked on it (0,I,II & III). I need to find out, to which speed the connection to a wire corresponds.
The motor looks somewhat like this:
**broken link removed**
As you can see, there are 2 stator coil windings to provide the field. The blue and orange wires split into two on approaching the motor and one of them gets connected to each stator winding, thus connecting the stator coils in parallel, whereas the yellow wire is connected only to one coil- the other coil is connected to the neutral(black) wire from the supply.
Thus, the connections to each stator winding are as follows:
1) yellow, orange, blue
2) neutral wire, orange, blue.
In addition, each of these windings are connected to the rotor through one of the brushes.

Thus,when the yellow wire is connected to the supply, the current flows through the first stator winding, then through some wires on the rotor, then through the second stator winding and back to the supply through the neutral wire connected to it. When the yellow wire is connected through the diode, the the rms voltage supplied would reduce to half, as current flows only during one half cycle.
However, when the orange or blue wires are connected, current can flow through the second winding and go to the neutral wire directly, in addition to the path mentioned for the current through the yellow wire.
How would this affect the speed of the motor? Morover, I can find no difference in the circuits formed by the blue and orange wires ( maybe, the difference lies in a portion of the motor, which is not visible externally.)
Above all, to which of the wires would the zero speed correspond to? This is the greatest puzzle for me.
If you can figure it out, please post the combination of wires and speeds.
In other words, match the following:
0 a)yellow wire through diode
I b) yellow wire directly
II c)blue wire
III d)orange wire

You were trying to repair the mixer. What was the original problem?
If it was not rotating, first of all check the carbon brushes. You may need to replace them.
Unless the motor itself is working, no permutation / combination for speed control is going to do any good.
 
Dear Sir,
What's the model of the diode around rotary switch? Is that 1N4001? or some thing else?
My Sumeet mixie's diode in the back of rotary switch literally fried. I need to replace that diode.
Thank you.

It is no "high tech" diode. Try 1N4007.
 
The clickable image is not reachable on my browser ( Mozilla Firefox). I suggest using a low-voltage stepdown transformer when checking the windings for proper reconnection to the motor.
 
Status
Not open for further replies.

Latest threads

New Articles From Microcontroller Tips

Back
Top