S 1 S 2 Russelectric BypassIsolation Switches Bypassing

S 1 S 2 Russelectric Bypass/Isolation Switches Bypassing Variations Restricted © Russelectric, A Siemens Company 2020 www. russelectric. com

Bypass/Isolation Switches Russelectric designs offer two ways to Bypass… 1. Fail-safe Bypass Unique Feature (Where simplicity of operation is critical during an emergency condition. ) 2. Maintenance Bypass (Where frequent maintenance of the ATS without interrupting the load is the overriding consideration. ) In this presentation we will study the principle of operation of Bypass/Isolation switches using dynamic animated one-lines. . .

Let’s begin with Russelectric Fail-safe Bypass Switches (Where simplicity of operation is critical during an emergency condition) Default state. ATS Section Let’s check out the indicator clusters… Note: For today’s discussion we will use bypass switches that have open transition transfer ATS’s built into them. LC Bypass Section S 1 LOAD S 2

Fail-safe Bypass Switches (Where simplicity of operation is critical during an emergency condition) Default state. ATS Section Let’s first review the basic operation of the Open Transition ATS Section LC ATS Bypass Section S 1 LOAD S 2

Fail-safe Bypass Switches (Where simplicity of operation is critical during an emergency condition) Default state. ATS Section ATS Shown in Source 1 position with Source 1 available LC ATS Bypass Section Source 1 Available ATS Connected to Source 1 S 1 LOAD S 2

Fail-safe Bypass Switches (Where simplicity of operation is critical during an emergency condition) Default state. ATS Section Upon loss of Source-1 an engine start signal is initiated and the engine/generator starts LC ATS Bypass Section S 1 LOAD S 2

Fail-safe Bypass Switches (Where simplicity of operation is critical during an emergency condition) ATS Section Upon loss of Source-1 an engine start signal is initiated and the engine/generator starts LC ATS Bypass Section S 1 LOAD S 2

Fail-safe Bypass Switches (Where simplicity of operation is critical during an emergency condition) ATS Section Once the engine/generator attains proper Source-2 voltage and frequency the ATS will transfer to Source-2 LC ATS Bypass Section S 1 LOAD S 2

Fail-safe Bypass Switches (Where simplicity of operation is critical during an emergency condition) ATS Section Once the engine/generator attains proper Source-2 voltage and frequency the ATS will transfer to Source-2 LC ATS Bypass Section S 1 LOAD S 2 When Source-1 returns the ATS will return to Source-1 and default mode after all timing functions are satisfied

Fail-safe Bypass Switches (Where simplicity of operation is critical during an emergency condition) Back to Default state. ATS Section Now let’s see the Bypass and Isolate handles… LC ATS Bypass Section S 1 LOAD S 2

Fail-safe Bypass Switches (Where simplicity of operation is critical during an emergency condition) ATS Section DEFAULT ISOLATE AUTO BS 1 LC ATS BS 2 Bypass Section Operation: Bypassing to source-1 supply… S 1 LOAD S 2

Fail-safe Bypass Switches (Where simplicity of operation is critical during an emergency condition) ATS Section DEFAULT ISOLATE AUTO BS 1 LC ATS BS 2 Bypass Section S 1 LOAD S 2 Halfway through handle travel load contacts open

Fail-safe Bypass Switches (Where simplicity of operation is critical during an emergency condition) ATS Section DEFAULT ISOLATE AUTO BS 1 LC ATS Bypass Section Upon full handle travel the S 1 Bypass Contacts close thus reconnecting the load to S 1 Power flows through Bypass Contacts to load. LOAD S 2 BS 2

Fail-safe Bypass Switches (Where simplicity of operation is critical during an emergency condition) ATS Section DEFAULT ISOLATE AUTO BS 1 LC ATS BS 2 Bypass Section Operation: Isolating ATS… S 1 LOAD S 2

Fail-safe Bypass Switches (Where simplicity of operation is critical during an emergency condition) ATS Section DEFAULT ISOLATE AUTO BS 1 LC ATS Bypass Section Operation: Isolating ATS… S 1 Note: Since ATS portion is disconnected the position indicator will go out BS 2 LOAD S 2

Key Benefit of the Fail-safe Bypass Switch… Fail-safe Bypass Switches (Where simplicity of operation is critical during an emergency condition) ATS Section DEFAULT ISOLATE AUTO BS 1 LC ATS Bypass Section S 1 LOAD S 2 BS 2

Scenario: Source-1 power is lost Fail-safe Bypass Switches (Where simplicity of operation is critical during an emergency condition) ATS Section DEFAULT ISOLATE AUTO BS 1 LC ATS Bypass Section S 1 LOAD S 2 BS 2

Scenario: Source-1 power is lost Fail-safe Bypass Switches (Where simplicity of operation is critical during an emergency condition) ATS Section DEFAULT ISOLATE AUTO BS 1 LC ATS Bypass Section BS 2 Engine Start Signal will initiate S 1 LOAD S 2

Fail-safe Bypass Switches (Where simplicity of operation is critical during an emergency condition) Scenario: ATS Portion fails to transfer to Source-2 X ATS Section DEFAULT ISOLATE AUTO BS 1 LC ATS X Bypass Section BS 2 Source-2 Power available S 1 LOAD S 2

Fail-safe Bypass Switches (Where simplicity of operation is critical during an emergency condition) A Fail-safe Bypass Switch can bypass to alternate source in one simple motion X ATS Section DEFAULT ISOLATE AUTO BS 1 LC ATS X Bypass Section BS 2 Source-2 Power available S 1 LOAD S 2

Fail-safe Bypass Switches (Where simplicity of operation is critical during an emergency condition) A Failsafe Bypass Switch can bypass to alternate source in one simple motion This is a considerable benefit to the Fail-safe Type Bypass Switch X ATS Section DEFAULT ISOLATE AUTO LC ATS X Bypass Section S 1 a LOAD S 2 Power flows through Bypass Contacts to load. BS 1 BS 2 Source-2 Power available

Engine Testing Scenario While ATS Racked Out Fail-safe Bypass Switches (Where simplicity of operation is critical during an emergency condition) ATS Section DEFAULT ISOLATE AUTO BS 1 LC ATS Bypass Section S 1 Unit shown bypassed to S 1 and ATS portion isolated LOAD S 2 BS 2 Operation: Testing Bypassing to The Alternate Source Engine Start Manually Initiated Engine Generator Starts

Engine Testing Scenario While ATS Racked Out Fail-safe Bypass Switches (Where simplicity of operation is critical during an emergency condition) ATS Section DEFAULT ISOLATE AUTO BS 1 LC ATS Bypass Section BS 2 Operation: Testing Bypassing to The Alternate Source S 1 LOAD S 2 Source-2 power Available Engine Generator Starts

Engine Testing Scenario While ATS Racked Out Fail-safe Bypass Switches (Where simplicity of operation is critical during an emergency condition) ATS Section DEFAULT ISOLATE AUTO BS 1 LC ATS Bypass Section S 1 LOAD S 2 BS 2

Engine Testing Scenario While ATS Racked Out Fail-safe Bypass Switches (Where simplicity of operation is critical during an emergency condition) ATS Section DEFAULT ISOLATE AUTO BS 1 LC ATS Bypass Section S 1 LOAD S 2 BS 2 The ATS may even be racked back in without making a mistake and without connecting the two sources of power.

Let’s move on to Russelectric Maintenance Bypass Switches (Where frequent maintenance of the ATS without interrupting the load is the overriding consideration. ) ATS Section LC Bypass Section S 1 LOAD S 2

Maintenance Bypass Switches (Where uninterrupted maintenance of the ATS is the overarching concern) Default state. ATS Section DEFAULT ISOLATE AUTO BS 1 LC ATS BS 2 Bypass Section In the Maintenance Bypass Versions the Load Contacts Overlap (to prevent load interruption when bypassing. S 1 LOAD S 2

Maintenance Bypass Switches (Where uninterrupted maintenance of the ATS is the overarching concern) ATS Section a DEFAULT ISOLATE AUTO BS 1 LC ATS Bypass Section a. X S 1 LOAD BS 2 Scenario: Bypassing S 2 Manually initiated electro-mechanical Interlocking required for this model Will not allow bypass to alternate source

Maintenance Bypass Switches (Where uninterrupted maintenance of the ATS is the overarching concern) ATS Section DEFAULT ISOLATE AUTO BS 1 LC ATS Bypass Section BS 2 Scenario: Bypass to Source-1 S 1 LOAD S 2

Maintenance Bypass Switches (Where uninterrupted maintenance of the ATS is the overarching concern) ATS Section DEFAULT ISOLATE AUTO BS 1 LC ATS Bypass Section BS 2 Scenario: Bypass to Source-1 Halfway through travel the load contacts and bypass contacts overlap preventing interruption of power to the load S 1 LOAD S 2

Maintenance Bypass Switches (Where uninterrupted maintenance of the ATS is the overarching concern) ATS Section DEFAULT ISOLATE AUTO BS 1 LC ATS Bypass Section BS 2 Bypass to Source-1 Upon completion of the bypass handle motion the load contacts open S 1 Power flows through Bypass Contacts to load. LOAD S 2

Maintenance Bypass Switches (Where uninterrupted maintenance of the ATS is the overarching concern) ATS Section DEFAULT ISOLATE AUTO BS 1 LC ATS Bypass Section S 1 LOAD S 2 BS 2

Maintenance Bypass Switches (Where uninterrupted maintenance of the ATS is the overarching concern) ATS Section DEFAULT ISOLATE AUTO BS 1 LC ATS Bypass Section Bypassing accomplished S 1 without load interruption Key Benefit of Maintenance Bypass Switch LOAD S 2 BS 2

Scenario: Bypassing to the alternate source Maintenance Bypass Switches (Where uninterrupted maintenance of the ATS is the overarching concern) ATS Section DEFAULT ISOLATE AUTO BS 1 LC ATS Bypass Section S 1 LOAD S 2 BS 2 Note: Bypass to (alternate) Source-2 cannot be accomplished until the ATS portion is in the alternate source position or isolated and removed from the equation

Scenario: Bypassing to the alternate source Maintenance Bypass Switches (Where uninterrupted maintenance of the ATS is the overarching concern) ATS Section DEFAULT ISOLATE AUTO BS 1 LC ATS Bypass Section BS 2 Using the same power failure Scenario as before, lets Imagine losing Source-1 and the transfer switch failing… S 1 LOAD S 2

Bypassing to the alternate source Maintenance Bypass Switches (Where uninterrupted maintenance of the ATS is the overarching concern) ATS Section DEFAULT ISOLATE AUTO BS 1 LC ATS Bypass Section BS 2 Using the same power failure Scenario as before, lets Imagine losing Source-1 and the transfer switch failing… S 1 LOAD S 2 Power goes out The engine will start automatically

Bypassing to the alternate source Maintenance Bypass Switches (Where uninterrupted maintenance of the ATS is the overarching concern) ATS Section DEFAULT ISOLATE AUTO BS 1 LC ATS Bypass Section BS 2 When generator achieves Proper voltage and Frequency the source 2 S 1 LOAD S 2 Bus becomes energized

Bypassing to the alternate source Maintenance Bypass Switches (Where uninterrupted maintenance of the ATS is the overarching concern) X ATS Section DEFAULT ISOLATE AUTO BS 1 LC ATS BS 2 Bypass Section Source-2 Power available. S 1 LOAD S 2 ATS fails to transfer

Maintenance Bypass Switches (Where uninterrupted maintenance of the ATS is the overarching concern) XX X ATS Section DEFAULT ISOLATE AUTO LC ATS Bypass Section In this instance unit can’t be bypassed until ATS is either isolated or manually switched to the alternate source. S 1 LOAD BS 1 X BS 2 Source-2 Power available. S 2 ATS fails to transfer

Maintenance Bypass Switches (Where uninterrupted maintenance of the ATS is the overarching concern) ATS Section DEFAULT ISOLATE AUTO BS 1 LC ATS BS 2 Bypass Section Source-2 Power available. S 1 LOAD S 2

Maintenance Bypass Switches (Where uninterrupted maintenance of the ATS is the overarching concern) ATS Section aa DEFAULT ISOLATE AUTO LC ATS Bypass Section S 1 BS 1 a LOAD S 2 BS 2 Source-2 Power available.

Maintenance Bypass Switches (Where uninterrupted maintenance of the ATS is the overarching concern) ATS Section DEFAULT ISOLATE AUTO BS 1 LC ATS BS 2 Bypass Section Move bypass handle to alternate source S 1 LOAD S 2

Bypassing to the alternate source Maintenance Bypass Switches (Where uninterrupted maintenance of the ATS is the overarching concern) ATS Section DEFAULT ISOLATE Load contacts Re-open AUTO BS 1 LC ATS BS 2 Bypass Section Move bypass handle to alternate source S 1 LOAD S 2

Bypassing to the alternate source Maintenance Bypass Switches (Where uninterrupted maintenance of the ATS is the overarching concern) ATS Section DEFAULT ISOLATE AUTO BS 1 LC ATS BS 2 Bypass Section Move bypass handle to alternate source Note: with the Maintenance Bypass Switch the ATS portion should be in the same source position as the Bypass contacts in order for the unit to be placed back into Default Mode. S 1 LOAD S 2 Power flows Through bypass Contacts to load.

Recap Russelectric designs offer two ways for Bypassing… • Fail-safe Bypass (Where simplicity of operation is critical during an emergency condition. ) Unique Feature Pro: Can bypass to either source in one simple motion regardless of the position or condition of the ATS portion Con: A short load interruption when bypassing between available sources Note: If combined with a UPS system no interruption will take place • Maintenance Bypass (Where frequent maintenance of the ATS without interrupting the load is the overriding consideration. ) Pro: No interruption of load when bypassing to the same source provided there is voltage present Con: Can only bypass the load to the same source that the ATS portion is connected to