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

Ac load current detection

sareehy

Junior Member level 1
Joined
May 16, 2016
Messages
15
Helped
0
Reputation
0
Reaction score
0
Trophy points
1
Activity points
121
Hi All,

I want to detect an ac load current if exceed a certain value
(eg 0.5 A) and then turn buzzer and led on .

Any suggestion ?

Regards 🙂
 

sanjue

Newbie
Joined
Jul 4, 2020
Messages
4
Helped
1
Reputation
2
Reaction score
1
Trophy points
3
Activity points
27
This is a better solution. There are two solutions: isolated and non-isolated. I recommend the isolated solution because of security.

Use a current transformer to collect the current in the loop, and then convert the current output by the current transformer to a voltage through a resistor, and then simply use a diode to rectify.

If you need precision, use the RMS chip directly.

At this time, you get a Voltage signal, this voltage signal can be compared with the reference voltage through a comparator, and then the output of the comparator is connected to a BJT or NMOS to drive the buzzer
 
Last edited by a moderator:

KlausST

Super Moderator
Staff member
Joined
Apr 17, 2014
Messages
17,422
Helped
3,937
Reputation
7,872
Reaction score
3,807
Trophy points
113
Activity points
115,509
Hi,

First you need to define
* the current ...instantaneous, true RMS, rectified average, what filtering method
* and define the waveform...frequency, sine, with or without overtones.
* the output signal timing .... referenced to the input signal

Klaus
 

sareehy

Junior Member level 1
Joined
May 16, 2016
Messages
15
Helped
0
Reputation
0
Reaction score
0
Trophy points
1
Activity points
121
Thank you all for reply ☺

The ac load is 220v/50 hz water pump .
 

KlausST

Super Moderator
Staff member
Joined
Apr 17, 2014
Messages
17,422
Helped
3,937
Reputation
7,872
Reaction score
3,807
Trophy points
113
Activity points
115,509
Hi,

I assume there are ready to buy solutions.

But if you want to uild it on your own:
* most probably you want to transform the AC current into a DC voltage signal
* then blank out effects of inrush current, pump start current
* add some hysteresis
* add some protection in case of errors, like huge overcurrent when a short circuit happens.

Consider:
* isolated or not
* what power supply

Klaus
 

treez

Advanced Member level 5
Joined
Sep 22, 2008
Messages
7,599
Helped
560
Reputation
1,123
Reaction score
536
Trophy points
1,393
Location
cambridge
Activity points
76,127
LEM do some good solutions for AC mains current CSTs
Also there are hall sensors by allegro.
 

Toggle Sidebar

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Top