MK-1 relays protect a motor by sensing the current going to the motor. Many of these use small heaters, often bi-metallic elements that bend when warmed by the current to the motor. When current is too high for too long, heaters open the relay contacts carrying current to the coil of the contactor.
A device with an overload protection used to control a motor is an Overload Relay.
overload model no Ke-FKR4(D)
a relay that detects the amperage the motor is drawing when the motor dwaws too much to drops out the coil voltage to shut down motor and prevent damage
one way is to use RTD sensor put inside the motor windings. The RTD sensor is connected to an electronic thermal overload relay. This type of relay can provide running temperature of the motor, on the electronic thermal over load relay display panel. RTD sensor is a wire wound resistor that changes resistance depending on the temperature
A motor protection circuit breaker (MPCB) is used to protect from overload and/or short circuit currents. An overload relay is used for overload only, and as such will have a relatively long delay before tripping. Also, I believe some overload relays are a one-use device (once tripped, they must be replaced), and I don't believe this is the case with MPCBs (could be wrong though). If you look at a manual for a MPCB, you'll see the tripping curve is two curves in one - at low currents, it is very slow (time in hours), but once you get above load currents, it speeds up significantly down to a few cycles, which is what you want for faults / short circuit conditions. An overload relay will have the first (slow) curve only. Do a google search for Cutler - Hammer (or go to their website) for some examples.
due to the extension of loads they are using the relays for protection.........
A device with an overload protection used to control a motor is an Overload Relay.
overload model no Ke-FKR4(D)
The primary purpose of Operation Overload was to open pathways into the country. The targets were the northern and western fronts.
The primary purpose of Operation Overload was to open pathways into the country. The targets were the northern and western fronts.
only the single phase monitored at which it installed
Protects the flasher relay from an overload or short.
No
Dashpot Overload Relay
The Purpose of a Relay is to control multiple electrical components at once.
An overload relay is like a bodyguard for your motor. Its job is to protect the motor from overheating if it’s working too hard. Here’s how it works, step by step: ⚡️ Motor draws current — When the motor runs, it pulls electricity from the panel. 📈 Too much current? — If the motor has to work harder than normal (maybe the machine is jammed or overloaded), it starts pulling more current than it’s supposed to. 🌡️ Overload relay feels the heat — The overload relay senses this extra current and starts getting warm. ⛔️ Relay trips and shuts down the motor — Once the relay gets too hot (because the motor is working too hard for too long), it trips — cutting power to the motor to protect it from damage.
The load current is made to flow through the thermal overload relay, which is actually a bimetalic strip. Beyond a prespecified current the bimetalic strip tend to deflect due to heat (thermal effect) thus cutting off the circuit and hence it acts as an over load relay protection.