Application notes
PS1021-2405-0000
29
Version: 1.0
Peak current voltage drops
Typically from 24V to 17V
At 10A for 50ms, ohmic load
Typically from 24V to 13V
At 25A for 2ms, ohmic load
Typically from 24V to 9V
At 25A for 5ms, ohmic load
4.2
Back-feeding loads
Loads such as braking motors or inductors can feed back voltage to the power supply. For the power supply,
this feature is also known as back EMF. (electromagnetic force).
This power supply is resistant and will not malfunction if a load feeds back voltage to the power supply. It is
irrelevant whether the power supply is switched on or off.
The maximum permissible feed-back voltage is 35Vdc. The absorbing energy can be calculated according to
the large built-in output capacitor indicated in the output data.
4.3
External input protection
The device is tested and approved for circuits that are fused up to 30A (UL) and 32A (IEC). External
protection is only required if the supply line has a protection that is higher than this. Also check the local
regulations and requirements. Local regulations may apply in some countries.
If an external fuse is required or used, minimum requirements must be taken into account to avoid false
tripping of the circuit breaker. A circuit breaker with a minimum value of 10A with B characteristic or 6A with
C characteristic should be used.
4.4
Parallel use to increase power
The power supply must not be connected in parallel to increase the output power.
4.5
Series connection
Power supplies of the same type can be connected in series to increase the output voltages. As many
devices can be connected in series as necessary, as long as the sum of the output voltages does not exceed
150Vdc. Voltages with a potential higher than 60Vdc are no longer regarded as safety extra-low voltage
(SELV) and can be dangerous. Such voltages must be protected with a contact hazard protection.
Grounding of the output is required if the sum of the output voltage is more than 60Vdc.
Avoid application of return voltage (e.g., from a braking motor or battery) to the output terminals.
Restrictions: Keep a mounting distance of 15mm (left/right) between two power supplies and do not install
the power supplies above each other.
Remember that leakage current, electromagnetic interference, input inrush current and harmonics increase
when using multiple power supplies.
