Braking resistor is connected with three four with five all models welcome to purchase

In the frequency control system, the motor deceleration and stopping is achieved by gradually reducing the frequency, and in an instant the frequency is reduced, the motor synchronous speed fall, but because of mechanical inertia of the motor rotor speed is not change. When the sync speed is less than the rotor speed, rotor current phase has changed almost 180 degrees, the motor from the state to the electric power generation state; at the same time, the torque of the motor shaft into the braking torque, the motor speed quickly decreased motor is regenerative braking. Motor regenerative electrical energy through the freewheeling diode full-wave rectified feedback to the DC circuit. Since electricity can not be reserved through the DC circuit rectifier bridge to the grid, capacitor absorbs the drive itself alone, although other parts of the energy consumption of electrical energy, but still short of the charge accumulation capacitance form a "pumping voltage", the DC voltage rise high. High DC voltage will cause damage to the various parts of the device. Therefore, the load in electricity generation stopping must take the necessary measures to deal with this part of the renewable energy. Processing methods of regenerative energy: dynamic braking and regenerative braking method works dynamic braking Dynamic braking is used in the inverter DC side plus discharge resistor unit, and the regenerative power consumption in power resistance up to achieve brake. This is the most direct way of treating renewable energy, which is renewable energy through special energy consumed in the brake circuit resistance, into heat, it is also known as "resistor braking," which includes a brake two parts unit and braking resistor. Functional brake unit brake unit when the DC link voltage Ud exceeds a predetermined limit value (such as 660V or 710V), turning energy circuit, the DC circuit way to release energy as heat through the braking resistor after. Built-in brake unit can be divided into two kinds and external, the former is suitable for low-power general-purpose inverter, the latter is applied to power converter or braking with special requirements in conditions. In principle, there is no difference between the two are as turned braking resistor "switch", which includes power management, voltage sampling comparator circuit and a drive circuit. Braking resistor braking resistor for regenerative energy from the motor to the consumption of thermal energy carrier, which includes resistance and power capacity of two important parameters. Usually used in engineering more corrugated aluminum resistance and resistance are two: The former uses vertical corrugated surface allows for heat dissipation to reduce parasitic inductance, and selection of high fire-retardant inorganic coatings, effective protection of the resistance wire will not be aging, extended life; the latter resistors weather resistance, shock resistance, superior to the traditional porcelain skeleton resistor, widely used in demanding harsh industrial environments, compact and easy to install, easy to additional radiator, good looks. Braking process dynamic braking is as follows: dynamic braking process is as follows: A, when the motor deceleration in the external force, reverse (including being dragged) The motor is running in the power generation state, energy is fed back to DC circuit so that the bus voltage increases; B, when the DC voltage reaches the braking unit ON state, the power brake unit turns on, current flows through the braking resistor; C, the braking resistor as heat energy consumption, the motor speed is reduced, the bus voltage is also reduced; D, bus voltage drops brake unit to shut off the value, the power MOSFET is off braking unit, braking resistor no current flows; E, sampled bus voltage, the brake unit repeats ON / OFF process, balancing the bus voltage, the system is running. Braking unit and braking resistor optional A, first to estimate the braking torque = ((motor inertia + motor load measured inertia converted to motor measured) * (before braking speed - speed after braking)) / 375 * deceleration time - load torque under normal circumstances, during the motor brake, there is a certain loss inside the motor, approximately 18% to 22% of the rated torque, so the results calculated at less than this range, then no need to pick brakes; square B, then calculates the braking resistor = brake element operation voltage value / (0.1047 * (braking torque -20% of the rated torque) * brake before the motor speed) In the brake unit operation, the DC bus voltage rise and fall depending on the constant RC, R is the braking resistor, C is the capacity of the electrolytic capacitor in the inverter. Here braking unit action voltage value is generally 710V. When C, and then select the brake unit of the brake unit making a selection, working the maximum current brake unit is the sole basis for selection, which is calculated as follows: braking current instantaneous value = braking unit DC bus voltage value / braking resistor value D, the final calculation of the braking resistor nominal power due to braking resistor is short-time working, therefore, according to the resistance characteristics and technical specifications, we know that the power consumption will be less than the nominal power resistor when power is applied, general Available the following formula: = average nominal power braking resistor power consumption characteristics of X brake duty% brake dynamic braking (braking resistor) has the advantage of simple structure descending rating factor X braking resistor during braking, The disadvantage is that the efficiency decreases, especially in the frequent braking will consume a lot of energy, and will increase the capacity of the braking resistor. Brake dynamic braking characteristics (braking resistor) has the advantage of simple structure, the disadvantage is reduced operational efficiency, especially in frequent braking will consume a lot of energy and will increase the capacity of the braking resistor. MM440 brake resistors for use with how to play its role should be used with a braking resistor Note: braking cycle selection P1237 while P1240 should be set to 0 to disable the DC voltage controller. Remember! Otherwise, the braking unit is not working, so the braking resistor is not heat! DC bus voltage regulator can serve to limit the effect of the DC link voltage increases, but it is achieved at the expense of braking torque, so be careful; braking resistor braking cycle is mainly chopper turned over time and braking resistor cooling time and choose what kind of cycle is not particularly important, the most important is the need according to your load is heavy duty load or clear, long braking time to choose.