About Power Supplies
General technical comments
With transformer equipped power supplies are important connecting links for the energy supply of electrical control systems. The distribution transformer brings the high line-voltage down to an usable secondary voltage level. In reference to the requirements this voltage might be converted into direct current (DC) by using rectifier units.
Mains line voltage
In dependence on the differential line voltages in several countries, power supplies must be adapted on this circumstances. The International Standard DIN IEC 38 has been achieved in order to standardize for many countries their main line voltage level. F E A S power supply units are especially designed to cover the whole range of different voltage levels. The scheduled realization of rearrangement of international main line voltages is shown as follows.
Transformer
The centre piece of any dc power supply is the distribution transformer. This transformer assured the isolation between the primary and secondary voltages and supplies the low voltage (max. 50Vac) which will be used to provide the power for control circuits or rectifier units. To generate a safety-low-voltage according to VDE 0551/EN 60742/ IEC 742 a special safety-transformer, equipped with separated winding coils, is needed in any case. The test voltage rate for this transformer should be 3,75 kV AC between the primary and secondary windings. It is relevant, that during this test an AC-voltage rate from min. 200V and max.450V is applied on the input side. Isolating transformers according to VDE 0550 are trans- formers with reinforced isolation between the primary and secondary windings.
Smoothed power supplies
Smoothed DC power supplies are unregulated units in which the transformer provides the secondary low voltage. This low AC voltage will be converted by the rectifier into a pulsing DC voltage and afterwards smoothed by electrolytic capacitors. The value of this DC voltage is approximately 1.42 times higher than the transformer secondary voltage. In dependency of the alternating loads the output voltage level will fluctuate accordingly. A great variation of the output voltage can be easily maintained with simple control circuits. The DIN 19240 describes the voltage tolerances clearly for electrical consumers to ensure a problemfree function within the release range.
Switch mode power supplies
With this development an optimal form of an AC/DC transformer for well regulated DC voltage is achieved. Basically it works like this: The AC line is rectified and filtered to give an acceptable DC voltage. A pulse width modulated switch chops the DC voltage into a high frequency pulsed waveform which is then converted via a high frequency power transformer, to the required voltage. This is subsequently rectified and filtered. The control circuit senses this output voltage, compares it with a reference thereby determining the duty cycle of the switching circuit and, therefore, the amount of energy transfered from the primary to the secondary of the high frequency power transformer. By using this method, as compared to a linear type, the power supply is able to work with varying load demands without having to dissipate surplus heat.
DC-UPS Accumulator packs with electronic charging contoller
For other versions/voltages contact us.
The Accumulator packs with electronic charging regulators are suited to buffer 12 Volt- or 24 Volt systems. They will ensure the power supply in case of a mains power failure and prevent the loss of your valuable data or the total breakdown of your production line. Regardless of for what you will apply the DC-UPS, you will always have the perfect protection against blackouts, which oftentimes can cause high costs.
The Accupacks LDR4012 and LDR4024 are suited to buffer 12-Volt- (LDR4012) or 24-Volt systems (LDR4024). The Accupack with integrated power supply is connected between mains and the application. In the event of a power failure, the implemented accumulator supplies the system connected to the outlet. The supply duration depends on the load current of the consumer.
The built-in switch-mode power supply allows to be operated at a wide range of input voltages (85 - 270 VAC and 150 - 400 VDC). During the online operation the power supply supplies the accumulator with optimal charging-voltage as well as the output load. The output-voltage hereby follows the batterie voltage level. The output-current of both types is up to 6.0 Amp.
In order to enable a remote monitoring of the storage battery, 2 relays are built in. The relay contacts can be loaded with a max. 8.0 Amp. by max. 250VAC or 48VDC and are routed to terminals.
