DRC-40B, CP-2005 power backup example

Power supplies, backup power supply 18.05.2020 11:26 18.05.2020 11:26

The DRC-40B power supply is a mains switching power supply with a fixed output voltage of 27.6 V, 1.45 A. It is suitable, for example, for powering Foxtrot control systems with a backup requirement in the event of a mains voltage failure. The power supply supplies the control system (connected load) and at the same time charges (keeps charged) the connected lead-acid batteries. In the event of a power failure, the power supply continues to supply the load from the connected battery.

The power supply is equipped with two transistor outputs AC OK and Bat Low.
The AC OK output transistor is closed when the correct mains voltage is at the input of the source.
The Batt Low output transistor is closed when the battery voltage is lower than 22 V (low battery signal).
The outputs are solved by open collector tracistors. The emitter (negative output terminal) is internally connected to the -V terminal (terminal 1).

The module does not require forced cooling, it is powered from the standard 230 VAC distribution network.

When switching the power supply input, it is necessary to take into account the maximum value of the inrush current up to 60 A (for more information, see this article). Recommended pre-fuse with fuse T 3.15 A.

The 230 V input of the power supply should always be treated against overvoltage. The article describes the basic principles of overvoltage protection, including examples of SPD type 3 and power supply.

The DRC-40B power supply meets the requirements for safety transformers and is a source of low safety voltage (SELV).

Tab. 1 Basic parameters of the DRC-40B power supply

Input voltage 90  ÷ 264 VAC
Input current type. 0,6 A / 230 VAC
Inrush current (cold start) max. 60 A / 230 VAC 
Output voltage 27,6 VDC 
Output current max. 1,45 A
Total output power continuous max. 40,02 W
Output short-circuit protection electronic
Switching off the battery at voltage 20 +/-1 V
Max. charging current 0,5 A
Max. switching voltage and current of outputs AC OK, Bat Low 50 V,  30 mA (outputs open collector)
Electrical resistance of input / output insulation 3000 VAC
Operating temperature -30 °C up to+70 °C (load. characteristics see Fig. 2.)
Dimensions

40 x 90 x 100 mm

 

Fig. 1. Example of CP-2005 backup power supply

Notes:

  1. The CP-2005 module does not have a "potential-free contact" binary input mode, so the AI0 and AI1 configurations are used to measure the resistance range 0 ÷ 2 kΩ and are evaluated as a resistance (almost zero or almost infinity). E.g. CP-2007 has a potential-free contact mode directly, it is possible to use DI mode directly there.
  2. The switched-off power supply, after connecting only the batteries, does not start supplying power to the output circuits, it must first be connected to the 230 VAC mains, then it works normally even when the mains voltage is disconnected.
  3. The CP-2005 module powered in this way, when backing up, for example, 2 pcs of 12 V, 9 Ah batteries (eg HR 1234W), will last approximately 55 hours from batteries (with minimal use of LTE communication).

 

  1. Fig. 2. Load characteristics of the DRC-40B power supply

     

    Fig. 3. Front view of the DRC-40B power supply, dimensions of the power supply module

     

    Fig. 4. Location of the DRC-40B power supply on a DIN rail