Twinsource Transfer Switch LogoRack-Mount Transfer Switches & Dual Cord Conversion Devices

Types of Rack-Mount Transfer Switches Offered By TwinSource

TwinSource offers two types of rack mount transfer switches for two applications. The two technologies can be used side by side for applications requiring different levels of reliability at the same data center.

The most critical applications would use our rack-mount automatic static transfer switch (RMSTS), and the less critical ones would use our electromechanical rack-mounted automatic transfer switch (RMATS). “Static” is also referred to as “solid state.” Both offer benefits best suited to the specific application. These applications are:

A) For highly mission critical applications where the cost of each outage is substantial and a Mean Time Between Failures (MTBF) in excess of 60M hours is expected we recommend our RMSTS (rack mount static transfer switch) - These are in use at many major data centers where each outage can cost hundreds of thousands to millions of dollars, as well as at process control applications where an outage can affect an entire manufacturing or power plant’s production capability (which can also add up to millions in losses). For these applications we offer our DCC-II Dual Cord Converter Rack-Mount Static Transfer Switch (RMSTS). They are 2 pole solid state SCR based full featured static transfer switches in current ratings of 30A, 40A, and 50A at voltages of 100V, 120V, 208V, 220V, 230V, and 240V in 50Hz and 60Hz for worldwide use. A 3 phase, 4-wire version has also been introduced that comes in one rating only at 208/120V, 50A, 18KW, 60Hz for high power rack applications. Dimensions are the same as the 50A, 1 ph unit except for being 10” longer. Weight is 65lb. Main features are:

  1. Super Fast (1/4 cycle) SCR Based Static Transfer Switch for high availability mission critical applications with a high fault (22KA) rating that is certified to UL1008 Standards.
  2. Transfers for all phase angle differences between sources.
  3. MTBF > 60 million hours.
  4. Continuous Duty 100% rated (i.e., a 30A switch is rated for 30A continuous and not just 24A at 80%).
  5. TUV Certified to UL1008 and CSA for Static Transfer Switch Standards. CE Labeled for international use.
  6. 4U high construction with a Plug-in Electronic Module (EM) that plugs into an outer Built-in Bypass Isolation Module (BM) with a 7 Position Bypass Isolation Selector.
  7. Built-in Voltage Suppression & Transient Protection to protect internal electronics.
  8. Completely user settable and configurable.
  9. Two isolated voltage-free summary alarm contacts.
  10. Optional Modbus RTU RS 485 Interface to connect to your Building Management System (BMS) for monitoring of all status and alarms.
  11. Optional Ethernet Translator Unit (ETU) for stand alone LAN/Web based monitoring of all status and alarms - can acknowledge alarms and records and archives data, allows remote preferred source selection, reports power quality at all racks for both sources, allows for independent monitoring and archiving away from the BMS if monitoring by the BMS is excessively costly.
  12. Optional Interlocks to prevent removal of the Electronic Module before Bypass Selector is in bypass isolate position and to not allow movement of selector if the EM has not been placed back into the unit after a maintenance action.

For a Word document of detailed purchase specifications, please contact us.

Download Single Phase Data Sheet (PDF) | Download Three Phase Data Sheet (PDF)

TwinSource 24A MagLatch Automatic Transfer Switch

B) For less critical applications where cost is a major consideration and the user is satisfied with an electromechanical type automatic transfer switch we offer our DCC-I Dual Cord Converter Rack-Mount Automatic Transfer Switch. They are 2 pole, electromechanical rack-mounted automatic transfer switches (RMATS) in current rating of 24A, at voltages of 100V, 120V, 208V, 220V, 230V, and 240V in 50Hz and 60Hz for worldwide use. They use our unique patented MagLatch technology (Patent #: US 7,535,129) whereby we minimize any possibility of contact failures and cross connections due to contact arcing and pitting as observed in relays that use single coil relays with contact springs to retransfer back, Vs. our dual coil relays with no contact springs and minimal arcing issues. Main features are:

  1. Fast Transfer (6-8 ms transfers for all in-phase & out of phase sources - unique to our patented technology) electromechanical design as a cost effective solution for a basic transfer switch, rated at 22KA with upstream protective devices.
  2. Transfers for all phase angle differences between sources.
  3. MTBF > 500,000 hours.
  4. Continuous Duty 100% rated at 24A.
  5. Certified to meet UL-IEC 60950 Standards for both domestic and international use.
  6. 1U high construction (without bypass).
  7. Completely user settable and configurable.
  8. Standard Remote Contacts as well as Optional Modbus RTU RS 485 Interface to connect to your Building Management System (BMS) for monitoring of all status and alarms.
  9. Optional Analogue Values Readings: V, A, KW, KVA, pf, f.
  10. Optional Waveform Capture - captures the waveform of the last transfer for diagnostic purposes and eliminates the need for costly rental of monitoring equipment in each rack.

For a Word document of detailed purchase specifications, please contact us. Download Data Sheet (PDF)

[Photos of typical sites where rack-mounted static transfer switches are used due to criticality of their operations.]

rack-mount static switch application photo



rackmount static transfer switch photo

rackmounted static transfer switch application photo



rackmount automatic static transfer switch application photo

rack-mount automatic static transfer switch application photo



Stand alone static transfer switches photo

rack-mounted static transfer switches photo


TwinSource USA • 32333 Aurora Road • Solon, Ohio, 44139, USA • (216) 408-2888
Contact: Fred Tamjidi • All sales inquiries: sales@twinsource.net • Technical inquiries: ftamjidi@twinsource.net

All specifications subject to change at supplier discretion without advance notification.

Types of Rack-Mount Transfer SwitchesTypical Installation of RM Transfer SwitchesBenefits of Static Transfer Switches
Implementation of Rack Mount Static Automatic Transfer SwitchesOverview of Automatic Transfer Switches
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