STR2-D33 Thermal Overload Relay

STR2-D33 Thermal overload relays work on the principle of the thermal effect of electric current. When a motor is overloaded, its current increases, causing the heating element inside the thermal overload relay to heat up. This heat is transferred to the bimetal, which is made of two metals with different coefficients of thermal expansion, so it bends when heated. When the bending reaches a certain point, it triggers a mechanical device, usually a contact, which disconnects the power supply to the motor, thus protecting it from damage.

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Product Description

Specifications:

Product Name	Thermal Overload Relay
Model	STR2-D33
Material	Plastic,Electronic Components
Thermal Contact	1NO+1NC
Thermal RelayRated Current	23A-93A	Pls note the current range
STR2-93	Adjustable Current Range(A)Setting Range	3322	23～26～32	STR2-40～95
		3353	17～25
		3355	30～33～36～40
		3357	37～41～46～50	STR2-50～95
		3359	48～51～60～65	STR2-50～95
		3361	55～0～65～70	STR2-62～95
		3363	63～71～80	STR2-80/STR2-95
		3365	80～85～93	STR2-95
Frequency	660V
Tripping Class	50/60Hz
Color	As Picture Shown

Main Techical Parameters

Model	Rated current	NO.	Setting Range(A)	For contactor
STR2-25	25	1301	0.1～0.12～0.14～0.16	STR2-9～32
		1302	0.16～0.19～0.22～0.25
		1303	0.25～0.3～0.35～0.4
		1304	0.4～0.05～0.63
		1305	0.63～0.8～0.9～1
		1306	1～1.2～1.4～1.6
		1307	1.6～1.9～2.2～2.5	STR2-12～32
		1308	2.5～3～3.5～4
		1309	4～5～6
		1312	5.5～6～7～8
		1314	7～8～9～10
		1316	9～11～13
		1321	12～14～16～18	STR2-12～32
		1322	17～21～25	STR2-12～32
		1353	23～32	STR2-25/32(LC1-D25/32)
STR2-36	36	2353	23～26～29～32	STR2-25/32(LC1-D25/32)
		2353	28～32～36	STR2-32
		2353	30～40	STR2-32
STR2-93	93	3322	23～26～32	STR2-40～95
		3353	17～25
		3355	30～33～36～40
		3357	37～41～46～50	STR2-50～95
		3359	48～51～60～65	STR2-50～95
		3361	55～0～65～70	STR2-62～95
		3363	63～71～80	STR2-80/STR2-95
		3365	80～85～93	STR2-95
STR2-140	140		80～104
			95～120
			110～140

Main Functions

Overload protection: When the load of the motor exceeds its rated value, the thermal overload relay will cut off the power supply to prevent the motor from overheating and damage.

Overheat Protection: If the motor overheats for some reason (e.g. high ambient temperature or poor heat dissipation), the thermal overload relay will also cut off the power supply.

Indication Function: Many thermal overload relays have an indication function, which signals or changes the status when the motor is overloaded or overheated, so that the operator can find and take measures in time.

Auto relay STR2-D series of thermal overload relay can be used in the circuit of 50/60 HZ, rated insulation voltage 660 V, rated current 0.1-93A for protecting the phase break when the electric motor is overload , the relay has different mechanism and temperature compensation can be pluged in ST1 series AC contactor,It is the most advanced thermal relay in the nineties in the world the products comply with IEC 60947-1.

Application Scenarios

Thermal overload relays are widely used in a variety of industrial and commercial environments, especially in equipment that requires electric motor drives. For example, they are used in pumps, compressors, fans, conveyors, and a variety of other mechanical equipment to ensure that such equipment can be safely shut down in the event of an overload or overheating condition.

Selection and Installation

When selecting a thermal overload relay, factors such as the motor's power rating, operating environment, and load characteristics need to be considered. It is also necessary to ensure that the rated current of the thermal overload relay matches the rated current of the motor and that it has appropriate overload and overheat protection characteristics.

When installing a thermal overload relay, you need to follow the manufacturer's guidelines and ensure that it is properly connected to the motor's power and control circuits. In addition, thermal overload relays need to be inspected and maintained regularly to ensure proper operation and long service life.

STR2-D33 Thermal Overload Relay