How to choose AC contactor, air open, and overheat relay for oil pump motor? How to wire the motor? Choose circuit breakers, thermal relays? Don't worry, Dalan Motor Xiaobian will answer you one by one!
How to consider the rated voltage of the motor, current wiring, circuit breaker and thermal relay according to the power of the motor. Three-phase two hundred and two motors, 5,000 amps. Commonly used three hundred and eight motors, one kilowatt two amperes. Low-voltage six hundred and six motors, kWh two amps. High-voltage three-kV motor, four kW-ampere. High voltage six kilovolt motor, eight kilowatts an ampere. A three-phase motor, in addition to knowing its rated voltage, must also know its rated power and rated current, such as: a three-phase asynchronous motor, 7.5KW, 4 poles (usually there are 2, 4, 6 grades, the number of stages Different, the rated current is also different), its rated circuit is about 15A.
1, circuit breaker: generally choose its rated current 1.5-2.5 times, commonly used DZ47-60, 32A.
2, wire: According to the rated current of the motor 15A, select the appropriate current-carrying wire, if the motor starts frequently, choose a relatively thick line, otherwise it can be relatively thin, the current-carrying flow has a relevant calculation, here we choose 4 square.
3, AC contactor, according to the motor power to choose the right size, 1.5-2.5 times, generally there is a model on its selection manual, here we choose Chint CJX2--2510, also have to pay attention to the matching of auxiliary contacts, do not buy when The auxiliary contacts are not enough.
4, thermal relay, its setting current can be adjusted, generally adjusted to 1-1.5 times the rated current of the motor.
How does the motor wire and select the circuit breaker?
(1) Multiple motors with wires: Adding the total power of the motor multiplied by 2 is their total current.
(2) The cross section of the conductor within 50 meters of the line is: the total current is divided by 4. (and then put a little margin)
(3) The length of the line exceeds 50 meters and the cross section of the conductor: the total current is divided by 3. (Appropriately put a little amount)
(4) The current density of large cables of 120 square meters or more is lower.
breaker:
(1) Circuit breaker selection: The rated current of the motor is multiplied by 2.5 times, and the setting current is 1.5 times that of the motor. This ensures frequent starting and ensures short-circuit action.
thermal relay? The setting of the thermal relay is 1.1 times the rated current of the motor.
AC contactor: AC contactor selection is 2.5 times the motor flow. This will ensure long-term and frequent work. Other answers are selected according to the current, but there must be a margin. Look at the nameplate of the motor. The current is very large. Only the thermal relay should be selected. The current of other things can be doubled. Mainly depends on the power of the motor, that is, the working current. The rated current of the AC contactor should be larger than the starting current of the motor. The air switch should be greater than or equal to the rated current of the contactor. The thermal relay generally has an adjustment range. The working current of the motor can be included in the range of the current adjustment of the thermal relay. The cable can be selected according to the magnitude and length of the motor current, and the copper cable per square millimeter in the short distance within 15KW can be about 3.5KW.
The rated power is the power marked on the nameplate of the motor. The calculation formula is that the current is equal to the power divided by (1.732 times the voltage multiplied by the power factor and multiplied by the efficiency). The power factor is generally 0.85, and the efficiency is generally 0.9.
----- Editor-in-Chief: Dalan Oil Pump Motor 02-Procurement Consultant
Copyright http: / (Dalan Motor) Reprint, please indicate the source
Http://news.chinawj.com.cn
Electric Supplies,Electric Supplies For Sale,Electrical Supply Store,Wholesale Electric Supply
Taiyaun JDS Machinery And Equipment Co., Ltd. , https://www.ccagoods.com