ZQM8X low-voltage molded case circuit breaker

Functions and characteristics

• TM thermal magnetic tripping unit can be used on ZQM8X-100/160/250/400/630 circuit breaker with breaking level f NH/S.
• There are two kinds of TM tripping units:
• TM-D —Used to protect distribution cables.
• TM-G —With lower threshold value, suitable for protecting generator or long cable Vigi leakage module can cooperate with all circuit breakers to provide leakage protection.

TM-D and TM-G Thermomagnetic Tripping Unit

Circuit breaker equipped with thermal magnetic release unit is mainly used in industrial and commercial electrical distribution field
TM-D is used to protect the cables on the power distribution system powered by the transformer.
TM-G is used to protect the generator (compared with the transformer, the shortcircuitcurrent is lower) and the distribution system with long cables (due to the high impedance of long cables, the fault current is smaller).

Protection

• Overload protection: thermal protection (Ir)
• The overload protection function is based on bimetal sheet and provides inverse time curve l2 .if the limit is exceeded, the deformation of the bimetallic sheet can trip the operating mechanism of the circuit breaker.
• Overload protection has the following characteristics:
• llr adjustment value is in amperes.The adjustable range is 0.7 to 1 time(16Ato 250A) of the rated current of the tipping unit.The current setting value of the corresponding series of tripping units is 11 to 250 A
• The time delay is not adjustable.
• Short circuit protection: magnetic protection (li)
• The li value of short-circuit protection function can be adjusted.Once the short-circuit current exceeds the set value,the circuit breaker will trip instantaneously.
• TM-D: the rated current is l6 to 160A, and li is not adjustable; The rated current is 200 to 630A, and li can be adjusted, and the adjustment range is 5 to 10×In.
• Protection type 3-pole.
• 3p3d: 3-pole shell frame (3p); All 3 poles are protected (3D)
• 3P2D: 3-pole shell frame (3P); Among them, two poles have protection (2D) , that is, three pole shell rame products.Only two poles have breaking units, and one pole is empty.4- pole
• 4P3D: 4-pole shell frame (4P); Three poles are protected (3D) (neutral line is not protected.
• 4P4D: 4-pole shell frame (4P); All 4 poles have protection (phase and neutral have the same protection threshold).