# Circuit design to control a 220V AC motor using a 0.1V SINE voltage source.

#### swakko

Joined Dec 17, 2018
11
I have an important electronics assignment that I'm not being able to solve at all.
Actually my subject says it all, we have a 0.1V 1KHz Sine voltage source, using some basic electronics (resistors, capacitors, transistors, diodes, op amps) we need to make a circuit in order to control an AC motor 220V (6A)

#### LesJones

Joined Jan 8, 2017
3,905
You need to give more information on EXACTLY what you have to do. Do you have to just switch the power on and off to the motor by switching the 1 Khz signal on and off for example. Another think it might mean is is to use it as a referance frequency to provide an AC power supply at some specified frequency to drive the motor. Is the motor an induction motor and if so is it single phase or three phase. Without knowing what you want to do no one can help you.

Les.

#### Alec_t

Joined Sep 17, 2013
13,232
Welcome to AAC! When you say "we need to make a circuit", do you have to actually build a circuit or just design it? There are various safety features you will need to consider, especially if you do have to build it.

#### swakko

Joined Dec 17, 2018
11
You need to give more information on EXACTLY what you have to do. Do you have to just switch the power on and off to the motor by switching the 1 Khz signal on and off for example. Another think it might mean is is to use it as a referance frequency to provide an AC power supply at some specified frequency to drive the motor. Is the motor an induction motor and if so is it single phase or three phase. Without knowing what you want to do no one can help you.

Les.
Thanks
@LesJones I just need to control the motor with that source. So I think it's your second option. And I just have to use basic electronics.

#### swakko

Joined Dec 17, 2018
11
Welcome to AAC! When you say "we need to make a circuit", do you have to actually build a circuit or just design it? There are various safety features you will need to consider, especially if you do have to build it.
Thanks

@Alec_t We just need to design it, on LTspice, any ideas?

#### Alec_t

Joined Sep 17, 2013
13,232
any ideas?
Yes. But this is your homework, so we don't give solutions, only guidance. Post your efforts at a circuit design, including your asc file, and we can help if you get stuck.

#### swakko

Joined Dec 17, 2018
11
Yes. But this is your homework, so we don't give solutions, only guidance. Post your efforts at a circuit design, including your asc file, and we can help if you get stuck.
I need some help to pass the course and this HW gives me extra points. Any help would be appreciated as the due is tonight.....

#### swakko

Joined Dec 17, 2018
11
Hello,

As said, please post any of your ideas, as given in the Homework Help rules.

Bertus
My idea is to make an amplifier but i don't know if it is possible to directly amplify that 0.1V to 220V
Also I wanted to try to use a relay but there is no relay component in the LTspice software.

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#### Alec_t

Joined Sep 17, 2013
13,232
Have you been taught about triacs?

#### bertus

Joined Apr 5, 2008
22,120
Hello,

You can not directly amplify from 0.1 to 220 Volts.
Also the frequencies are different (0.1 Volt 1kHz, 220 Volt 50 or 60 Hz.)
You could amplify the 0.1 Volts 1 kHz to a level that can be detected.
With the detected signal, you could drive a conventional relay or Solid State Relays to switch the 220 Volts.

Bertus

#### swakko

Joined Dec 17, 2018
11
Hello,

You can not directly amplify from 0.1 to 220 Volts.
Also the frequencies are different (0.1 Volt 1kHz, 220 Volt 50 or 60 Hz.)
You could amplify the 0.1 Volts 1 kHz to a level that can be detected.
With the detected signal, you could drive a conventional relay or Solid State Relays to switch the 220 Volts.

Bertus
Exactly what I wanted to do but the problems is that there is no relays in LTspice, do you know how to get a relay in that software?

#### swakko

Joined Dec 17, 2018
11
Have you been taught about triacs?
No... We can just use basic electronics (Capacitors, opamps, transistors, relay, resistors..)

#### bertus

Joined Apr 5, 2008
22,120
Hello,

There are several relays in LTspice:

Bertus

#### swakko

Joined Dec 17, 2018
11

#### bertus

Joined Apr 5, 2008
22,120
Hello,

You will have an old version.
I have looked in LTspive IV and in there you will not find the [magnetic] library.
Try to get a newer version.

Bertus

#### swakko

Joined Dec 17, 2018
11
Hello,

You will have an old version.
I have looked in LTspive IV and in there you will not find the [magnetic] library.
Try to get a newer version.

Bertus
I HAVE LTspice XVII and still can't find it. Which version do you recommend me to get ?

#### bertus

Joined Apr 5, 2008
22,120
Hello,

Have you tried to do a field update?
You can find at tools > sync release.

Bertus

#### swakko

Joined Dec 17, 2018
11
Hello,

Have you tried to do a field update?
You can find at tools > sync release.

Bertus
Yes, I just did that .... IDk what's the problem