Variable Frequency Drives Bypass Options

Mechanically Interlocked VFD Bypass Operation Two Contactor Bypass Power Supply SED2 Drive Mechanically Interlocked Drive Output Contactor The Eco has been designed and is tailor-made by Siemens exclusively for HVAC applications. Family of Variable Speed Drives with common: software hardware layout user interface Fan & Pump Motors have variable torque-speed characteristics torque is proportional to the square of the speed, T=k x (rpm)2 this means a small low speed load torque and a large high speed load torque. load inertia (especially large fans) can be quite high so getting up to setpoint speed may take a few more seconds User Benefits of Variable Speed Drives overall energy and cost savings along with improved comfort levels through better regulation. Bypass Contactor Motor 1

Mechanically Interlocked VFD Bypass Operation Three Contactor Bypass Power Supply Optional Input Contactor SED2 Drive Mechanically Interlocked Drive Output Contactor The Eco has been designed and is tailor-made by Siemens exclusively for HVAC applications. Family of Variable Speed Drives with common: software hardware layout user interface Fan & Pump Motors have variable torque-speed characteristics torque is proportional to the square of the speed, T=k x (rpm)2 this means a small low speed load torque and a large high speed load torque. load inertia (especially large fans) can be quite high so getting up to setpoint speed may take a few more seconds User Benefits of Variable Speed Drives overall energy and cost savings along with improved comfort levels through better regulation. Bypass Contactor Motor Optional “3rd” drive input contactor electrically isolates the VFD 1

Bypass Types – Conventional and Electronic Conventional bypass – uses hard- wired electrical components for mechanical bypass control Switches Fuses Relays Electronic bypass – electronic logic control with simple keypad Reduced wiring and mechanical components Improved system reliability Additional logic features standard Interlocked Start 2 Safety circuits Smoke Purge logic Conventional Bypass Electronic Bypass

SED2 Conventional Bypass VFD and Bypass cabinet mounted on common back plate Conventional electromechanical control Indicating lights, selector switches, relays All voltages and HP ratings Configurations available: Disconnect (fused on non- fused) NEMA 1 cabinet 2 or 3 contactor control manual/auto bypass selection standard line/load reactor option Damper end-switch logic option

Conventional Bypass Components Protective cover Gland Plate Conduit Connector Mounting Back Plate Bypass ON Indicator Light Drive /Off / Bypass Selector Line Disconnect Drive Test Selector (3 contactor only)

Conventional Bypass Components Line reactor (optional) Control transformer Input contactor (optional) Control relays Power fuses (optional) Output contactor Line disconnect Bypass contactor Motor overload relay Field wiring terminals

Conventional Bypass Power Range A-F denotes VFD frame size For more info, see the Bypass menu on this CD

Electronic Bypass Features Easy-touch keypad with status display Common remote start/stop Auto bypass Essential service mode Interlock start logic Disconnect options Disconnect Fused Disconnect Circuit Breaker Two and three contactor models 6 digital inputs and 6 digital outputs Optional line or load reactor

Electronic Bypass Components Electronic control board Input contactor (optional) Field wiring terminals Line reactor (optional) Power fuses (optional) Control transformer Line disconnect Output contactor Bypass contactor Motor overload relay

Electronic Bypass Keypad Easy-touch electronic keypad displays status and operating configuration Indicates current status with 14 LEDs Built -in logic reduces wiring and ensures safe operation

Electronic Bypass Keypad Features Indicates that input contactor is closed and drive has power. Indicates input contactor is closed when on, close pending when flashing. Toggling this button opens / closes the input contactor. Enables hand bypass mode. Enable remote bypass. Bypass light w/ flash. Contactor closes and light comes on when Remote Start input closes. Enable closes both drive input and output contactors. Essential service light flashes when this feature is activated. Auto Bypass light flashes when this feature is activated. Disconnect the motor whether in drive or bypass mode. Indicates that one of the safety inputs is open. Indicates that either the overload input has closed or that the thermal overload has tripped. Indicates present operational state of interlocked start logic.

For more info, see the Bypass menu on this CD Electronic Bypass Power Range A-F denotes VFD frame size For more info, see the Bypass menu on this CD

Siemens SED2 VFD Advantages Low harmonics design Small enclosure size Many standard features Reduces operating cost Low power losses/high efficiency Minimal effect on customer power Wide power range – from ½ to 125 HP