Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronic Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

Register Log in

[SOLVED] Driving contactor coil with dimmer

Status
Not open for further replies.

adnan_merter

Full Member level 3
Joined
Jan 23, 2008
Messages
160
Helped
6
Reputation
12
Reaction score
6
Trophy points
1,298
Location
The most beautiful city of the world
Activity points
2,521
Hello everybody, first i apologize if this a repetitive question, i checked the forum and couldnt see a relevant topic.

Recently i bought a contactor for my project but accidentally i bought one with a 24vac coil instead of 220vac coil. I tried to exchange it but no luck.

I have an option buying 220/24vac transfomer but if possible i would like to use a dimmer circuit. The coil draws not more than 1 amp.
 

barry

Advanced Member level 5
Joined
Mar 31, 2005
Messages
5,033
Helped
1,102
Reputation
2,214
Reaction score
1,087
Trophy points
1,393
Location
California, USA
Activity points
27,564
I'd be really reluctant to try and use a dimmer here. A dimmer does not lower the voltage, it only turns the AC off for part of the cycle. Plus, standard light dimmers are not designed for inductive loads.
 

adnan_merter

Full Member level 3
Joined
Jan 23, 2008
Messages
160
Helped
6
Reputation
12
Reaction score
6
Trophy points
1,298
Location
The most beautiful city of the world
Activity points
2,521
I'd be really reluctant to try and use a dimmer here. A dimmer does not lower the voltage, it only turns the AC off for part of the cycle. Plus, standard light dimmers are not designed for inductive loads.
Thanks for reply, i know dimmer doesnt lower the voltage, it changes the on/off time, thus changes total energy consumed over time. I can design a new dimmer circuit with snubber for inductive loads.

The question is, can the coil endure peak voltages in a short while?
 

KlausST

Super Moderator
Staff member
Joined
Apr 17, 2014
Messages
18,894
Helped
4,205
Reputation
8,413
Reaction score
4,145
Trophy points
113
Activity points
124,212
Hi,
The question is, can the coil endure peak voltages in a short while?
I doubt any one here can give you a guarantee.
All we can do is guess. Since we even don´t know which motor from which manufacturer.

The only way for you to get reliable informations is to:
* read the datasheet if there is an according specification
* or contact the manufacturer.

Klaus
 

adnan_merter

Full Member level 3
Joined
Jan 23, 2008
Messages
160
Helped
6
Reputation
12
Reaction score
6
Trophy points
1,298
Location
The most beautiful city of the world
Activity points
2,521
Hi,

I doubt any one here can give you a guarantee.
All we can do is guess. Since we even don´t know which motor from which manufacturer.

The only way for you to get reliable informations is to:
* read the datasheet if there is an according specification
* or contact the manufacturer.

Klaus
I guess the only way to know if it is possible or not, is experiment it.

I will try tomorrow and let you know the result. Thank you.
 

KlausST

Super Moderator
Staff member
Joined
Apr 17, 2014
Messages
18,894
Helped
4,205
Reputation
8,413
Reaction score
4,145
Trophy points
113
Activity points
124,212
Hi,

I don´t agree.
An experiment is no valid test.

I´m rather sure that a properly designed triac circuit will work ... but there are safety regulations. You can´t test them. Safety isolation, clearance ...
And if it works for 5 minutes it does not mean it will work for years. I expect higher mechanical stress, maybe higher noise ... maybe higher wear out of isolation...

Klaus
 

adnan_merter

Full Member level 3
Joined
Jan 23, 2008
Messages
160
Helped
6
Reputation
12
Reaction score
6
Trophy points
1,298
Location
The most beautiful city of the world
Activity points
2,521
Hi,

I don´t agree.
An experiment is no valid test.

I´m rather sure that a properly designed triac circuit will work ... but there are safety regulations. You can´t test them. Safety isolation, clearance ...
And if it works for 5 minutes it does not mean it will work for years. I expect higher mechanical stress, maybe higher noise ... maybe higher wear out of isolation...

Klaus
I understand your concerns but i will use it to power my personel workbench, neither commercial nor critical application, and i will always be there when the coil is energized. I totally agree with you, i expect noise because of switching. It will be just an experiment not a suggestion or tutorial.
 

dick_freebird

Advanced Member level 5
Joined
Mar 4, 2008
Messages
7,120
Helped
2,087
Reputation
4,178
Reaction score
1,934
Trophy points
1,393
Location
USA
Activity points
57,125
A 24VAC line transformer ought to be dirt cheap and
common at electrical / electronic surplus (incl eBay).

HVAC controls commonly use 24VAC to run the hot
side (compressor, fan, solenoid valve) relays so you
can probably find new and not-expensive at home
supply and hardware stores.
 

wwfeldman

Advanced Member level 3
Joined
Jan 25, 2019
Messages
787
Helped
185
Reputation
370
Reaction score
193
Trophy points
43
Activity points
5,785
your jury rigged gadget will probably work for a (short) while
and blow up when you can least afford it

you are much better off getting a step down transformer
and learning a lesson on ensuring that what you buy is what you want.
 

adnan_merter

Full Member level 3
Joined
Jan 23, 2008
Messages
160
Helped
6
Reputation
12
Reaction score
6
Trophy points
1,298
Location
The most beautiful city of the world
Activity points
2,521
your jury rigged gadget will probably work for a (short) while
and blow up when you can least afford it

you are much better off getting a step down transformer
and learning a lesson on ensuring that what you buy is what you want.
Thanks for advice :) Lesson already learnt. I am new at power electronics and getting experience from mistakes. But for sake of curiosity i will try dimmer and for long term operation i will order a transformer. Case closed.
 

KlausST

Super Moderator
Staff member
Joined
Apr 17, 2014
Messages
18,894
Helped
4,205
Reputation
8,413
Reaction score
4,145
Trophy points
113
Activity points
124,212
Hi,

An autotransformer could do if you don't need isolation.

Klaus
 

Status
Not open for further replies.

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Top