The DC contactor adopts a modular design, which can assemble the customer's required number of contact points and the customer's required contact forms (normally open, normally closed and converted) with a minimum of parts; this series of products have high contact breaking voltage , And use horizontal blowing magnetic arc extinguishing, the maximum breaking voltage can reach 220VDC. The product is suitable for program-controlled power supply or uninterruptible power supply system, forklift, electric vehicle, construction machinery system.
DC contactor selection method
1. Select the type of DC contactor: The type of DC contactor should be selected according to the type of load current and the weight of the load, that is, AC load or DC load, light load, normal load or heavy load.
2. Rated current of the main contact of the DC contactor: The rated current of the main contact of the DC contactor can be calculated according to an empirical formula. IN main contact ≥ PN motor/(1~1.4) UN motor If the motor controlled by the DC contactor is started, Frequent braking or reversing, generally reduce the rated current of the contactor's main contact by one step.
3. Rated voltage of the main contactor The rated voltage on the nameplate of the contactor refers to the rated voltage that the main contact can bear, not the voltage of the attraction coil. In use, the rated voltage of the contactor main contact should not be less than the rated voltage of the load.
4. Selection of operating frequency: The operating frequency refers to the number of times the contactor switches off per hour. When the on-off current is large and the on-off frequency is too high, the contact may be severely overheated or even welded. If the operating frequency exceeds the specified For the value, a DC contactor with a rated current of one level should be used.
5. Selection of coil rated voltage: The coil rated voltage is not necessarily equal to the rated voltage of the main contact. When the line is simple and there are few electrical appliances, the voltage of 380V or 220V can be directly used. If the line is complicated, the use of electrical appliances exceeds 5 hours, and 24V is available. A coil of 48V or 110V (36V, 110V, or 127V as stipulated internationally in 1964).
When choosing a contactor, pay attention to
1. The rated voltage of the main contact ≥ the rated voltage of the load.
2. The rated current of the main contact is ≥ 1.3 times the rated load current.
3, coil rated voltage. When the circuit is simple and the use of electrical appliances is small, 220V or 380V may be selected. When the line is complicated, and the electrical appliance is used in more or less safe places, 36V, 110V or 127V may be used.
4. The number and type of contacts of the contactor should meet the requirements of the control circuit.
5, the operating frequency (on the number of contacts per hour). When the on-off current is large and the on-off frequency exceeds the specified value, a contactor model with a rated current of one level should be used. Otherwise, the contacts will be severely heated and even welded together, causing the motor and other loads to run in phase loss.
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