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57 Threads found on edaboard.com: Relay Protection
Hi, There are ready to buy isolating solid state relays. Use one with zero cross acting. Klaus
Hello, i have one of those AC motion sensors that are powered directly from 230V mains and provide switched AC phase output. I've connected 12V/6A (notebook-like) PSU to it to power 12V/3A LED stripes. However it seems that relay contacts get welded together from time to time. (It does not switch off until i punch the motion sensor box to make
Emergency switch: You can use the "DPDT Emergency switch" for both circuits. Select the contact rating of switch such that maximum out of two circuits. It will avoid additional circuits like relay. Fuse: If you select the fuse for stall current, it provides motor protection under stall conditions and it may not protect the motor from overheati
I have a 4 k.v main line voltage stabilizer. Brand= High-tech When the input is 200/210v=> output 220/240v (silent/normal) When the input is 130/140/150/160v=> OUTPUT 300v (noisy,loud) Please tell me the reason behind it and what will be the cost to fix it. I have already repaired this stabilizer for relay loop/ tak tak problem and then this
Use a voltage sensing relay and a contactor?....simple but effective.
I am looking at Safety relays for a 3 phase motor system. A number of them have a reset function. can I wire this in as a start button?
Since the most destructive spikes and surges in the 12vdc circuit in vehicles are when the alternator switches on and off, if I know when the alternator is going to switch on or off, can I use a relay to isolate a sensor I want to use to measure something like battery voltage? Or can the bad stuff come through the ground?
Dear all, I have design a filter bank, consisting of 6 low pass filters with different cut off frequencies. Each filter is sandwiched in two relays. relays have 50ohm contact resistance. problem is when I connect my 50Watt PA at the input of this filter bank, some filter relays start buzzing and I have lost couple of PA due to this (...)
Hello everybody! I would like to ask a question about energizing a relay from a digital output in source mode. 113291 Is it correct to put the flywheel diode parallel to the coil just to prevent the voltage spike due to the e.m.f. of the coil through my ground (when switching of the digital output)? Thanks in advance.
Brief Introduction of the project: Three phase induction motor overload protection relay using a microcontroller based circuit. Parameters being Monitored by Microcontroller: Three phase current consumed by the motor. Parameters known: Motor's rated current Service factor Locked rotor current of motor Locked rotor withstand time. How
I have a 30A 12v relay to drive a single phase instrument. So I am using 18v transformer to provide relay coil voltage through transistor bc337. But my problem is that after some days I noticed that my transistor becomes short and relay operates without firing transistor. Actually I don't know what is bc337-25 collector voltage range. So (...)
I have a PIC16F628A system which operates a 12V DC Coil 230V 30A Contact rating relay. I am not using opto coupler to avoid a dual 12V secondary transformer. The current cunsomption is < 500 mA. So, I am using a single 12V 1A power supply. I feel MCU will hang due to EMI and noise in power line due to relay switching. The relay has back emf (...)
In my application, I need to drive DC motors at 24 V without speed control. I have choosen 2 SPDT relays as the solution. When either of them is turned ON , it switches GND at the Common pin of relay which is otherwise at 24 V (NC). Although this configuration seems to work perfectly, I am facing an unusual issue. Sometimes the relay gets (...)
I am working on FPGA based relays. Now want to communicate that relay with other or central control station. We are now need the frame format of any relay communication standard as 61850 or any other and each field of that frame format whether it require float value or integer value or any other. What should be width of (...)
If you just need back emf protection for a relay driver, then you can just put a big bidirectional TVS device across the motor. Do you actually need speed/voltage/current control?
A standard way is to wire a relay with a diode in series with it across the input power terminals of your device. When the power is of the correct polarity the relay pulls in and passes the power to the device. Frank
The proposed mutiple-tap transformer solution: yes it's simple, but requires the use of switching relays, ... Thanks anyway. No need for relay, triacs can be used to. By the way relay is not expensive. :-)
dear all, any one please tell me the what is N/V in attached circuit.what is the use of that and how it is going to work?
hi there is another option by using pic16f676 or any other pic having built in adc. u have to make coding in this manner that when voltages acceeded above limit it switch switch relay to cut i/p.
Hai...i am doing a project which is based on embedded system.its a digital motor protection relay for three phase induction motors.The microcontroller which i am using is renasas R8C/2C microcontroller.The relay has two phase CT's and one CBCT to measure the line current of the three phases and the secondary of CT is inputed to (...)