At present, most European & Asian countries’ civilian standard AC voltage is single phase 220V (230v, 240v), 50Hz (single-phase two-wire, power frequency 50 Hz), industry standard is three-phase 380V (400v, 415v, 420v), 50Hz (three-phase four-wire system, three-phase three-wire system).
United States and Canada AC power supply frequency are both 60Hz, according to American National Standard For Electric Power Systems, commonly used single-phase and three-phase electrical system as follows:
Civilian use 110 – 120V 60Hz single phase three wire system. There is a neutral line, the voltage between the neutral and the other two lines is 120V 60 Hz, and the voltage between the other two is 240V 60 Hz (neutral line and ground line are separated). 110-120V 60Hz single phase three wire system can be made 120V 60Hz single phase voltage power supply for low-power handheld and mobile devices, such as power tools, lamps, fan and other appliances. It can also be provided to small machinery 240V 60Hz single phase voltage equipment. Due to the reasons for the access side of substantially, 110v-120V, 240V standard power supply voltage will drop to 110V and 230V.
Industrial use 460v – 480V 60Hz three phase four wire system, 277V three phase four wire system: Single-phase voltage is 277V, phase voltage is 480V. So the industrial three-phase power is divided into two voltages, respectively 230V three-phase four-wire and 480V three-phase four-wire system. Electric power tools and motor-based machines sold in the United States usually labeled as a single-phase 110V 60Hz, single phase 230V 60Hz, three-phase 230V 60Hz and three-phase 480V 60Hz.
For example, a single phase 230V 60Hz motor-based equipment on the US market, if you run it on single phase 220V 50Hz power supply, then there will be serious problems occur, which will affect the motor quality directly, reduce the motor life, leading to the motor’s capacitors burning or even exploding.
1. Severe heating, no-load current increasing
When the power frequency decrease from 60Hz to 50Hz, it means the flux per pole increase 20% corresponding, and the magnetic flux density of each part of the motor will also increase by 20%. Due to the motor design of the magnetic flux has very small margin, it will greatly increase the load current for more than 20%. Since the magnetic flux density than the original increase of 20%, the saturation magnetic flux density of the core. In addition, with the speed of the decline in ventilation effect deteriorate, the motor temperature rises much higher than running it at 60Hz.
2. The power and rotation speed decrease
If the no-load current approaches or exceeds original rated current, the motor cannot be operated; if the load current is still a wide gap between the motor capacities of at least 20% or more less than the original and the motor speed can be decreased by about 17% at 50Hz running.
3. Starting current increase rapidly, easy to overload
Motor is inductive load, so the reactance value is proportional to the power frequency, the lower of the power frequency, the lower of the reactance value. The starting current is inversely proportional to the reactance in, the motor starting current will correspondingly than the original increase of about 20%.
4. Designed torque severely damage
Torque is inversely proportional to the size of the square of the power supply frequency. When the power supply frequency is changing from 60Hz to 50Hz, torque is increased. Similarly, the motor maximum torque and minimum torque will be increased. Motorists know what torque is, however, the increase in torque where power is not increased, but to undermine the design specifications of the motor.
5. Significantly shorten the life of the motor
Iron consumption is about 1.3 and power is proportional to the square of the magnetic flux density and frequency, so that the iron loss increases 14%. Motor output power greatly reduced, so that the efficiency of a certain decline, exacerbated by losses in the motor hardware components to shorten the life of the motor.