RTS30 ATS
INDUSTRY’S MOST COMPREHENSIVE LINE OF UL TESTED 30-CYCLE-RATED AUTOMATIC TRANSFER SWITCHES
Russelectric® RTS Series automatic transfer switches are the most complete line of 480 VAC 30-cycle-rated and 3-cycle-rated UL tested switches available today.
TESTED, LISTED, AND LABELED BY UL UNDER UL-1008
Before Underwriters’ Laboratories, Inc. will allow a transfer switch to be listed with a short circuit rating, it requires that the switch be able to close in on the same amount of fault current as it can withstand. All Russelectric RTS Series automatic transfer switches have been fully tested, listed, and labeled for 30-cycle and 3-cycle closing and withstand ratings (A) under UL-1008.
In applications where extremely high short circuit current is available, fuse protection is mandatory. When coordinated with current limiting fuses, Russelectric RTS Series transfer switches have UL listed closing and withstand ratings of 200,000 amperes.
RTS30 30-Cycle Automatic Transfer Switches are available in the following versions:
Open & Closed Transition
Open-Transition
- Quick-break, quick-make, high-speed transfer mechanism
- Positive mechanical and electrical interlocking
- Simple electrical operators
- Rapid arc quenching
- Safe external manual operator provides same quick-break, quick-make operation as electrical operator
- 3- and 4-pole configurations
- Front accessible wiring
- RPTCS ATS Control System
RTS30 30-Cycle Rated Automatic Open-Transition Switches are available in the following versions:
Single Operator
FOR BASIC POWER TRANSFER APPLICATIONS
Single-operator RTS Series version “A” automatic transfer switches offer a dependable means of transferring power from one source to another and back again using open-transition transfer. These switches are ideal for resistive load applications where no time delay (to allow inductive load voltages to decay) is needed.
Dual Operator
FOR LARGE MOTOR AND HIGH INDUCTIVE LOAD TRANSFER APPLICATIONS
Dual-operator RTS Series version “B” automatic transfer switches allow inductive loads to be re-energized with normal inrush starting current after transfer. These inductive loads typically involve large 3-phase motors or transformers.
A time delay between the opening of the closed contacts and the closing of the open contacts allows large motor loads to demagnetize before transfer. This prevents the severe “bump” caused by switching a rotating motor (which momentarily acts as a generator) from one source to another source that is not in synchronism. This transition time delay is approximately 400 milliseconds, but it may be increased through the switch’s controller.
Closed-Transition
FEATURES | A
- High-speed quick-make, quick-break, closed-transition transfer
- Rapid closed-transition retransfer to preferred source and for testing with zero power interruption
- Simple electrical operators
- Rapid arc quenching
- 2-, 3-, and 4-pole configurations
- Front accessible wiring
ZERO POWER INTERRUPTION ON RETRANSFER OR TESTING
RTS Series version “C” closed-transition transfer switches offer the advantage of zero power interruption during both testing and automatic retransfer to Source 1. They are built to the same stringent standards as Russelectric®’s widely respected break-before-make switches. They are identical in size to open transition switches.
HIGH-SPEED OPERATORS PROVIDE TRANSITION IN LESS THAN 100 MILLISECONDS | B
To provide the rapid transition necessary to achieve the absolute minimum time in which both Source 1 and Source 2 are simultaneously connected to the load, Russelectric uses special high-speed operators. Transfer occurs only when both sources are within an acceptable window of synchronization. Tests show that transition times are substantially less than 100 milliseconds.
OPEN-TRANSITION TRANSFER, CLOSED-TRANSITION RETRANSFER, AND TESTING
1| Transfer upon loss of Source 1
Upon reduction of Source 1 voltage below a preset value after a preset time delay, the Russelectric RTS C signals the engine generator (Source 2) to start. When the engine generator has reached acceptable voltage and frequency, the transfer switch transfers to the engine generator source in open transition. The load is served by the engine generator until the ATS detects return of Source 1 to acceptable values. After a preset time delay to allow stabilization of Source 1, the ATS is ready to retransfer.
2| Retransfer upon return of power to the preferred source
When the Russelectric RTS C is ready to retransfer, a synch-check function initiates transfer once the engine generator is in synchronism with Source 1. After the open contacts (Source 1) have closed, the closed contacts (Source 2) open, providing closed-transition transfer.
The period of time in which both sets of contacts are closed is less than 100 milliseconds. A separate timer monitors the closed-transition period, and initiates a signal to reopen the set of contacts that have just been closed, should the closed-transition time exceed the setting of the timer. In addition, a safety signal is provided for customer-connected alarm or remote breaker tripping should the closed-transition period exceed the timer’s setting. Should Source 2 power fail at any time after Source 1 has returned, but before the stabilization time delay relay has timed out, the ATS will automatically open-transition retransfer to Source 1.
3| Load test
Upon initiation of load test, the ATS signals the engine generator (Source 2) to start. When the engine generator has reached acceptable voltage and frequency, a synch-check function initiates transfer to the engine generator in closed transition by closing the Source 2 contacts and then opening the utility (Source 1) contacts. The closed-transition time is less than 100 milliseconds. After the load test period, retransfer to Source 1 is also closed-transition as previously described. The timer monitoring excessive closed transition transfer time is active during this operation. Failure of the generator source during load test will result in automatic open-transition retransfer to the utility source.
