How much bleed resistance is on the power supply's output?

  • Knowledge Base ID: 1012
  • Product Type: MagnaDC
  • Category: Hardware

The MagnaDC programmable DC power supply output consists of a large bank of capacitors used to filter output ripple. In parallel with these capacitors, a resistive bleeder circuit is provided to discharge the capacitors to safe levels when the power supply is not in use. The bleeder circuit is transparent to the product's voltage and current measurements. As the output of the power supply is regulated at the product's output terminals, the bleeder will be out of the circuit while the supply's output is enabled. When the power supply is in standby or switched off, the bleeder circuit will apply a load on the DC bus. If a discharge into the power supply's output is undesired, a blocking diode will prevent, for example, batteries or capacitors connected to the DC bus from bleeding into the power supply's output when the power supply is in standby or turned off.

The amount of bleed resistance varies by power level and the model's peak output voltage rating. While the high voltage or high power product utilize passive resistance rated for the peak voltage of unit, the low- to medium-voltage products utilize a constant power electronic bleeder, providing near equal loading at all voltage levels. Table 1 provides the integrated bleed resistance for the MagnaDC rack-mount products. Table 2 provides the integrated bleed resistance for MagnaDC floor-standing products.

Table 1. Output bleed resistance for MagnaDC rack-mount programmable DC power supplies

  SL Series XR Series TS Series
Power Level 1.5 kW to 4 kW 2 kW to 10 kW 5 kW to 15 kW  20 kW to 30 kW 45 kW
Voltage Range All ≤ 1000 Vdc > 1000 Vdc ≤ 1000 Vdc > 1000 Vdc ≤ 1000 Vdc > 1000 Vdc ≤ 1000 Vdc > 1000 Vdc
Bleeder Resistance (Watts) 25 25 50 25 50 50 100 75 150
Constant Power (Yes/No) Yes Yes No Yes No Yes No Yes No

Table 2. Output bleed resistance for MagnaDC floor-standing programmable DC power supplies

  MS Series MT Series
Power Level 30 kW 45 kW 60 kW 75 kW 100 kW to 250 kW
Voltage Range ≤ 1000 Vdc > 1000 Vdc ≤ 1000 Vdc > 1000 Vdc ≤ 1000 Vdc > 1000 Vdc ≤ 1000 Vdc > 1000 Vdc All
Bleeder Resistance (Watts) 50 100 75 150 100 200 125 250 500
Constant Power (Yes/No) Yes No Yes No Yes No Yes No No

Last Modified: July 14, 2014 - 12:46

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