Piller Product History APOTRANS

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APOTRANS
For automatic transfer of alternative infeeds





Fast static switch for automatic no-break load transfer

Simple solution for supplying critical loads from independent sources

Practically unlimited security of supply when used in conjunction with UPS systems

High equipment reliability thanks to redundant control electronics

APOTRANS Fast static switch for automatic no-break load transfer

Requirements
The present-day demands that critical loads make on reliable power sources are so high that dependency on only one secure busbar may not be sufficient. However, if, in the event of failure of one supply, there is a facility for a transparent changeover to a second supply, then the overall reliability of the supply system is substantially enhanced.

Application:
n + 1 redundancy with 3 different types of UPS sets

Solution with simple changeover
During malfunctions in the preferred power supply, the APOTRANS automatic transfer switch offers the facility for changing over to an alternative infeed. The system consists of two static switches, one of which is connected to the preferred supply and the other to the alternative supply. The outputs of both static switches together supply the load. For maintenance purposes, an additional bypass switch permits no-break changeover from one supply to the other. The static switches can also be isolated by means of manual isolating switches.

Mode of operation
In normal operation the pre-selected infeed is switched through to the load via a Thyristor switch. If the selected infeed fails, or the voltage no longer meets the quality requirements, the system changes over automatically to the other source. If the pre-selected supply is again available and remains stable for a specified time, the load is automatically switched back to the preferred infeed. This function can also be disabled so that the retransfer can only be made manually.


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Short-circuit protection
If a short-circuit occurs in the downstream load network, no transfer takes place from the active to the inactive source. The static switch switches off if the short-circuit is not removed within a specified time interval.

Safety
Both static switches consist of three anti-parallel double Thyristor modules. Control, measurement and monitoring is carried out via the redundant microprocessor controller. The transfer process is phase-selective and takes place in the current zero crossing, that is to say the changeover is made phase by phase L1-L1, L2-L2 and L3-L3. This prevents circulating currents from flowing between the two infeeds.



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Overload capacity
2 minutes at 1.5 times rated current or 100 milliseconds at 10 times rated current.

Monitoring (Operator control and display unit)
The control unit with information display contains an LED function display, an optional four-line, 80-digit illuminated LC display, as well as all necessary operator control buttons

Interfaces
All operator control and status messages are transmitted via an RS 485 or RS 232 interface.

APOTRANS
Automatic load transfer system
No-break changeover between different supplies

The APOTRANS consists of two 3-phase microprocessor-controlled static switches connected in parallel, each with its own service bypass, supplying one common outgoing feeder.

Each static switch consists only of thyristors connected in anti-parallel, without the use of filter capacitors or commutation devices.

Redundancy: The APOTRANS contains redundant control electronics and cooling fans to ensure maximum reliability

Reliability: The availability for load connection of two independent infeeds considerably increases reliability and in combination with 2 UPS sets the supply is substantially enhanced.

The transfer can be made manually, automatically or by an external signal.



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Click here to view APOTRANS Specifications.