GL-20 series current relayDetailed product description：

1 Purpose
This relay is used for overload and short-circuit protection of motors, transformers, and transmission lines, and can also be used for overcurrent protection in AC operating circuits. Suitable for use in protection circuits with specific action time requirements for inverse time limits and definite time limits.

2. Action principles and structural characteristics
2.1 Action principle
The operating principle of this series of relays is composite, consisting of two components: inductive and electromagnetic, which share a common coil. When the coil of the relay passes through an alternating current, two magnetic fluxes with a certain phase difference are generated in the shielding part of the iron core. As a result of the interaction between these magnetic fluxes and the eddy currents induced in the disk, a torque is generated on the disk. At an operating current of 20-40%, the disk begins to rotate. At this time, the relay does not operate because the fan teeth and worm gear are not engaged.
When the current in the coil increases to the set current, the electromagnetic torque is greater than the reaction torque of the spring, and the frame rotates, causing the fan teeth to mesh with the worm and rise. At this time, the moving iron of GL-21, 22, and 25 overcurrent relays is pushed by the toothed top rod, causing the air gap on the right side of the magnet to decrease and the air gap on the left side to increase. Therefore, the moving iron is attracted by the magnetic conductor, causing the relay contacts to move.
GL-21、 The 22, 23, and 24 type relays have a dynamic closing main contact, which can also be modified into a dynamic breaking contact as needed.
GL-25、 The 26 type relay has a conversion main contact with a large contact capacity, ensuring that the secondary circuit of the current transformer will not open during the relay operation.
GL-23、 In addition to the main contacts mentioned above, the 24 and 26 type relays also have a pair of signal contacts operated by inductive elements, and the main contacts are only controlled by electromagnetic elements.
When the current in the relay coil is less than the instantaneous setting value, the action time limit of the inductive element is inversely proportional to the current. When the current in the input coil reaches a certain multiple of the set current (i.e. instantaneous setting value), the electromagnetic component will act instantaneously. Therefore, the action time limit of the relay has the characteristics of definite time limit and inverse time limit.
2.2 Structural Features
The relay has seven taps to adjust the operating current of the inductive and electromagnetic components. The operating current of electromagnetic components can also be adjusted by changing the air gap between the moving iron and the electromagnet. The relay has a mechanism for adjusting the action time setting value of the sensing element and a main contact action signal board. This signal board can be reset by a mechanism installed on the housing to return after its action.
The components of the relay are mounted on a metal base and covered with a transparent organic glass shell.
The relay is installed on a vertical panel and can be wired in front or behind the board.
The internal wiring diagram of the relay is shown in Figure 1.



Figure 1 Internal wiring diagram of GL-20 series relay (back view)

3 Technical data
3.1 The rated data and adjustment range of various relays are listed in the following table

relay model	rated current (A)	Setting value
		Action current of sensing element (A)	● Action time (S)	● Electromagnetic component action Current multiplier
GL-21／10 GL-21／5	ten five	4；5； 6；7； 8；9； ten 2；2.5； 3；3.5； 4；4.5； five	0.5； l；2； 3；4	2；4； 6；8
GL-22／10 GL-22／5	ten five	4；5； 6；7； 8；9； ten 2；2.5； 3；3.5； 4；4.5； five	2；4； 8；12； sixteen	2；4； 6；8
GL-23／10 GL-23／5	ten five	4；5； 6；7； 8；9； ten 2；2.5； 3；3.5； 4；4.5； five	2；3； four	2；4； 6；8
GL-24／10 GL-24／5	ten five	4；5； 6；7； 8；9； ten 2；2.5； 3；3.5； 4；4.5； five	8；12； sixteen	2；4； 6；8
GL-25／10 GL-25／5	ten five	4；5； 6；7； 8；9； ten 2；2.5； 3；3.5； 4；4.5； five	0.5； 1；2； 3；4	2；4； 6；8
GL-26／10 GL-26／5	ten five	4；5； 6；7； 8；9； ten 2；2..5； 3；3.5； 4；4.5； five	8；12； sixteen	2；4； 6；8

When operating at 10 times the current
The ratio of the operating current of electromagnetic components to the operating current of inductive components.
3.2 The relay coil is allowed to withstand 110% of the rated current in the long term.
3.3 The return coefficient of the sensing element should not be less than 0.85 for GL-21 and 22 relays, and not less than 0.85 for GL-23, 24, 25, and 26 relays
The relay should not be less than 0.8.
When the current is equal to the operating current of the sensing element, the power consumption of the relay shall not exceed 15VA.
The on/off capacity of 3.5 contacts.  
3.5.1 GL-21、 The 22 type dynamic contact and GL-23, 24 type dynamic contact can be connected for a long time when the voltage is not greater than 220V
DC or AC 5A, but when disconnecting the connected circuit, other contacts should be used. For example, using auxiliary contacts of the oil switch.
GL-21、 The 22 type dynamic breaking contact and GL-23, 24 type dynamic breaking main contact can disconnect AC 2A when the voltage is not greater than 220V. If the controlled circuit is powered by an inverter and connected in parallel with the relay contact, and the total impedance is not greater than 4 Ω when the current is 4A, then the relay contact can be shunted and disconnected when the current in this circuit reaches 50A.
3.5.2 GL-23、 The 24 and 26 type dynamic signal contacts can disconnect or connect DC 0.2A or AC lA when the voltage is not greater than 220V.
3.5.3 GL-25、 Type 26 main contact, when the controlled circuit is powered by an inverter and its impedance is not greater than 4.5 Ω at a current of 3.5A, the main contact can shunt and disconnect the circuit when the current is not greater than 150A.
3.6 The dielectric strength of each circuit of the relay can withstand alternating current for non charged metal parts and between circuits that are not electrically connected
50Hz， Voltage of 2kV, no breakdown or flashover for 1 minute.
3.7 The insulation resistance of each circuit of the relay to non electrified metal parts and between circuits that are not electrically connected shall be measured with a 500V megohmmeter and shall not be less than 300M Ω.
The weight of the 3.8 relay shall not exceed 3.1kg.
The shape and installation hole size of the 3.9 relay are shown in Figures 1, 2, and 3, respectively.

a) Pre board wiring

b) Rear wiring of the board

GL-20 series current relay