Siemens MM440 inverter power brake start / stop cycle - Database & Sql Blog Articles

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Brand AVX TPSE226M035R0125 Low impedance tantalum capacitor AVX 22

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Parameter P1237=MM440 dynamic brake start/stop cycle setting is a percentage. I would like to ask if this percentage is for the inverter DC bus voltage. If I set 20%, if the DC bus normal voltage is 580V, press 20%. To calculate, when the DC bus voltage is 696V, the brake unit is put into operation. When the brake unit is below 696V, is the brake unit turned off?
Answer: 1. P1237 refers to the start/stop cycle of the dynamic brake, not the ON level of the DC bus voltage dynamic brake. This parameter is used to define the ratio of the duty/stop time (duty factor) of the dynamic braking resistor (chopper resistor). When the cycle time expires and the voltage of the DC bus exceeds the ON level of the dynamic brake, the dynamic brake is immediately applied.

2. Regarding your question, “When the DC bus voltage is 696V, the brake unit is put into operation, and when the brake unit is cut off below 696V, the brake unit is turned off.” In fact, the above is the “power brake turn-on level”. "problem. The details are explained below.

If the parameter P1254 (automatic detection of the ON level of the DC voltage loop) = 0, then the brake unit is put into operation, the braking resistor is connected to the voltage value = 1.13 * 1.414 * P210 (ie the supply voltage);
If parameter P1254=1, the brake unit is put into operation, and the braking resistor is turned on voltage = 0.98*r1242.