A device with an overload protection used to control a motor is an Overload Relay.
MOTOR CONTROL CENTER. A motor control center consists of one or more vertical metal cabinet sections with power bus and provision for plug-in mounting of individual motor controllers. Very large controllers may be bolted in place but smaller controllers can be unplugged from the cabinet for testing or maintenance. Each motor controller contains a contactor or a solid-state motor controller, overload relays to protect the motor, fuses or a circuit breaker to provide short-circuit protection, and a disconnecting switch to isolate the motor circuit. Three-phase power enters each controller through separable connectors. The motor is wired to terminals in the controller. Motor control centers provide wire ways for field control and power cables. Each motor controller in an MCC can be specified with a range of options such as separate control transformers, pilot lamps, control switches, extra control terminal blocks, various types of bi-metal and solid-state overload protection relays, or various classes of power fuses or types of circuit breakers. A motor control center can either be supplied ready for the customer to connect all field wiring, or can be an engineered assembly with internal control and interlocking wiring to a central control terminal panel board or programmable controller.
An electrical circuit is designed to carry a certain amount of energy, or voltage. The flow of energy, called a current, should travel through the path from one point to the other unimpeded. If that current is interrupted, it causes what is commonly known as a short circuit. If an electrical system is designed properly, overload protection kicks in to stop the flow of energy until the source of the interruption is removed.
overload model no Ke-FKR4(D)
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
Remove the motor from the system. Get the motor rewound at a motor rewinding shop. Replace the motor back into the system. While the motor is at the rewind shop find out why the motor burnt out. The first thing that should be checked is the overload protection. Make sure that is is the same as the motors full load amps.
If the overload protection is set correctly to the motors full load amperage, any overloading of the motor will trip the protection and take the motor off line. Once the reason of the overload has been established and rectified, the overload protection is reset and the motor can be brought back on line.
due to the extension of loads they are using the relays for protection.........
It is protection installed to protect, usually motors, from going beyond the amperage capacities that were set down by the manufacturer's specifications of the motor. As a motor loads up to its rated HP it will operate within the motors amperage range. More loading on the motor will increase the amperage draw to a point where the motor's winding will start to burn or short out due to insulation breakdown of the motor coils. Over load protection is a settable device that will limit the current to a specific value. The setting on the over current device is the motor's FLA (full load amps). If the motor amperage goes higher that the set point the overload protection, the overload protection contacts will open and drop the motor's magnetic contactor off line. In some cases this could be an annoyance but it does save the motor from destroying itself.
There are many types of overload protection these days and all are based on the FLA (full load amps) of the motor.
It depends on what your definition of a normal relay is. If it is a small plug in relay to control the motor's contactor then there is no point. All pump motors need control to start and stop the pump. Whether it is done from a pressure switch or a float system it doesn't matter they both should control the motor's contactor and not the pump directly. Most small relays do not have the amp capacity in their contacts to handle inductive loads. Using a motor contactor also has the benefit to protect the motor with overload protection. Using the overload contacts in series with the control device allows the pump to go off line should an overload occur.
If it is on a motor, it is called a self or auto resetting IEC thermal overload protection device. If it is on anything else, it is a bad idea.
On a star delta starter a motor overload or a motor going to ground and cause a short circuit will cause the overload protection to trip. These overloads have to be reset before the motor can be restarted.
1)Instantaneous overcurrent protection. 2.Ground fault protection. 3.Thermal overload protection. 4.Stalling Protection. 5.Phase unbalance protection.
Look on thew nameplate of the motor to see if it is thermally protected. This means that there is overload protection on the inside of the motor next to the windings. If the temperature rises in these windings the motor will trip off line and stop. Once the motor cools down the thermal overload device will reset and the motor will start again the next time you try it. As the answer states below reduce the load. <<>> How about over heating. To much load caused by bad bearings. Simply to much load.
The RPM of the motor will momentarily slow down, the current will go higher until the motor gets up to speed again. The motor will then go back to normal operation. If the load is in excess of the horse power rating of the motor, the motor will go into overload and the current will go higher that nameplate rating. If left in this condition the overload protection should trip the motor off line. If there is no protection on the motor, the life span of the motor is shortened likely from insulation failure.
SIMOCODE is a motor management system provided by SEIMENS, which helps to circuit overload protection, control & communication capabilities in a single package for motors. Currently it has two type that is SIMOCODE pro C & SIMOCODE pro V. SIMOCODE pro V is more advance & it use for more complex applications. Another features of SIMOCODE pro motor management system is the amount of information that can be monitored, collected & communicated, high degree of details on status & performance of each motor load is possible by using this. - Ramakant Kanojiya.
Yes a 208 voltage motor will operate on 220 volts. You have to increase the motor overload protection by 10% of the motor's full load amperage to protect the motor.