Thermal relay pdf

1. What is a thermal relay?
2. What is the IEC standard for thermal overload relay?
3. What are the different types of thermal relays?
4. What is 95 and 96 on overload relay?
5. What is used of thermal relay?
6. What are the uses of thermal relay?
7. How do you calculate thermal overload relay?
8. What is 51N relay?
9. What are 2 types of overload relays?
10. What is L1 and L2 in a relay?
11. What is A1 and A2 on a relay?
12. What is the difference between IEC 60439 vs IEC 61439?
13. What IEC 60947?
14. What IEC 61439?
15. What IEC 62271?

What is a thermal relay?

A relay that opens or closes contacts with a bending mechanism as a result of the difference in the expansion coefficients of a bimetal, which is heated by the current. The thermal relay switches a magnetic contactor to protect a motor from overload.

What is the IEC standard for thermal overload relay?

Tripping classes of the thermal overload relays

The tripping class indicates according to IEC 947-4-1 the maximum tripping time in seconds under specified conditions of test at 7.2 times the setting current and specifies tripping and non tripping times for 1.5 and 7.2 times the setting current.

What are the different types of thermal relays?

There are three types of thermal overload relays — bimetallic, eutectic, and electronic.

What is 95 and 96 on overload relay?

The normally closed overload contact are terminals 95 & 96; and the normally open overload contact are terminals 97 & 98. T1 T2 and T3 are the load terminals. The normally closed control circuit contact will open when there is a fault, this contact is typically used in series with the control circuit.

What is used of thermal relay?

Thermal relays are protective electrical appliances used for overload protection of motors or other electrical equipment and electrical circuits.

What are the uses of thermal relay?

Thermal overload relays are economic electromechanical protection devices for the main circuit. They offer reliable protection for motors in the event of overload or phase failure. The thermal overload relay can make up a compact starting solution together with contactors.

How do you calculate thermal overload relay?

Thermal Overload Relay setting = 120%x Full Load Current(Phase) Max. Thermal Overload Relay setting = 120%x4 = 4 Amp.

What is 51N relay?

In solidly-grounded medium voltage systems, the most common choice for ground fault protection is to add a fourth relay in the residual connection of the CT's to monitor the sum of all three phase currents. This relay is referred to as a residual ground overcurrent or 51N (or 50/51N) relay.

What are 2 types of overload relays?

Overload relays are typically one of two types: thermal relays or electrical relays. The overload mechanism inside thermal relays consists of a bimetallic strip in conjunction with a heating element.

What is L1 and L2 in a relay?

1. The two vertical lines that connect all devices on the relay logic diagram are labeled L1 and L2. The space between L1 and L2 represents the voltage of the control circuit. 2. Output devices are always connected to L2.

What is A1 and A2 on a relay?

What Do A1 and A2 Mean on a Contactor? A1 and A2 on a contactor typically refer to either end of the electromagnetic coil assembly. Most contactor manufacturers use A1 and A2 to designate the two terminals connecting electrical power to the contactor's magnetic coil.

What is the difference between IEC 60439 vs IEC 61439?

Summarising: With the currently used IEC 60439, the rule is “one part for each type of AssEMBLY”. With the new IEC 61439 the rule is “two parts for each type of AssEM- BLY”.

What IEC 60947?

IEC 60947-1:2020 applies, when required by the relevant product standard, to low-voltage switchgear and controlgear hereinafter referred to as "equipment" or “device” and intended to be connected to circuits, the rated voltage of which does not exceed 1 000 V AC or 1 500 V DC.

What IEC 61439?

IEC 61439 defines which points the manufacturer and the user of a switchgear and controlgear assembly have to define. The switchgear and controlgear assembly is viewed as a so-called black box, whose interfaces to the environment are defined in 4 areas. Further information on this topic: black box concept.

What IEC 62271?

IEC 62271-200 is the part of the IEC 62271 series of standards for metal-enclosed switchgear and controlgear for rated voltage from 1kV to 52kV. In 2021, these standards were updated to the third edition.