Common use of VAC Clause in Contracts

VAC. The bypass control board shall include an auxiliary power supply rated 24 VDC, 250 mA. Drive isolation fuses shall be provided. Bypass designs which have no such fuses, or that only incorporate fuses common to both the drive and the bypass are not acceptable. Third contactor “isolation contactors” and service switches are not an acceptable alternative to drive isolation fuses. The bypass shall be able to detect a single-phase input power condition before the bypass contactor closes or while running the motor in bypass, by monitoring all three phases of input voltage. Relying on a high current trip if the motor is single-phased is not acceptable. The bypass shall be designed for stand-alone operation and be completely functional in both Hand and Automatic modes, even if the drive and/or drive’s control board has failed. Network communications shall remain functional. Bypass systems that do not maintain full functionality in the event of a drive failure, are not acceptable. All bypasses shall have the following software features as standard: Programmable loss-of-load (broken belt / coupling) indication shall be functional in drive and bypass mode. The bypass shall also support run permissive and start interlock control functionality, including start delay, as previously specified in the drive section. The bypass control shall monitor the status of the drive and bypass contactors and indicate when there is a welded contactor contact or open contactor coil. The bypass shall include a selection for either manual or automatic transfer to bypass. The automatic transfer mode shall allow the user to select the specific drive fault types that result in an automatic transfer to bypass. The automatic transfer mode shall not allow a transfer to bypass on motor related faults. Automatic transfer schemes that do not differentiate between fault types, are not acceptable. The bypass shall include the ability to select the operating mode of the system (Drive/Bypass) from either the bypass control panel or digital input. The bypass shall include the ability to know the phase sequence and provide a phase sequence fault to indicate if the bypass and drive would run the motor in the opposite direction, this feature shall be enabled by default The bypass shall include a supervisory control mode that monitors the value of the drive’s analog input (feedback). This feedback value is used to control the bypass contactor on/off state. The supervisory mode shall allow the user to maintain hysteresis control over applications such as cooling towers and booster pumps. Selectable Class 10, 20, or 30 electronic motor overload protection shall be included in both drive and bypass mode. The drive and bypass shall be designed to operate as an integrated system when in Override mode. Whether operating in drive or bypass mode, the low priority safeties will be ignored, and high priority safeties will be followed. External start/stop commands will be ignored. There shall be four selectable Override modes: Bypass only, with two smoke control modes: Fixed pre-configuration of digital inputs Configurable high/low priority safeties and faults, to allow configuration to meet needs of local Authority Having Jurisdiction. Drive only Drive then transfer to bypass, in the event of a drive fault Force to Stop Before the bypass circuit can be tested in commissioning, the drive must start the motor to check for shorts and ground faults Network communications – the bypass shall include BACnet MS/TP, ▇▇▇▇▇▇, and ▇▇▇▇▇▇▇ Controls N2 as standard. The bypass BACnet implementation shall be BTL Listed to Revision 14 or later. Optional communication cards for BACnet/IP, LonWorks, Profibus, Profinet, Ethernet/IP, Modbus TCP, and DeviceNet shall be available. The bypass relay output status, digital input status, warning and fault information can be monitored over the network. Status information shall be monitored, including; operating mode (drive vs bypass), current drawn in bypass mode, broken belt, and phase-to-phase voltage. The bypass start/stop command, force to bypass command, and relay outputs shall be capable of being controlled over the network.

VAC. The bypass control board shall include an auxiliary power supply rated 24 VDC, 250 mA. Drive isolation fuses shall be provided. Bypass designs which have no such fuses, or that only incorporate fuses common to both the drive and the bypass are not acceptable. Third contactor “isolation contactors” and service switches are not an acceptable alternative to drive isolation fuses. The bypass shall be able to detect a single-phase input power condition before the bypass contactor closes or while running the motor in bypass, by monitoring all three phases of input voltage. Relying on disengage the motor, and provide a high current trip if the motor is single-phased is not acceptablephase input power indication. The bypass shall be designed for stand-alone operation and be completely functional in both Hand and Automatic modes, even if the drive and/or drive’s control board has failed. Network communications shall remain functional. Bypass systems that do not maintain full functionality in the event of a drive failure, are not acceptable. All bypasses shall have the following software features as standard: Programmable loss-of-load (broken belt / coupling) indication shall be functional in drive and bypass mode. The bypass shall also support run permissive and start interlock control functionality, including start delay, as previously specified in the drive section. The bypass control shall monitor the status of the drive and bypass contactors and indicate when there is a welded contactor contact or open contactor coil. The bypass shall include a selection for either manual or automatic transfer to bypass. The automatic transfer mode shall allow the user to select the specific drive fault types that result in an automatic transfer to bypass. The automatic transfer mode shall not allow a transfer to bypass on motor related faults. Automatic transfer schemes that do not differentiate between fault types, are not acceptable. The bypass shall include the ability to select the operating mode of the system (Drive/Bypass) from either the bypass control panel or digital input. The bypass shall include the ability to know the phase sequence and provide a phase sequence fault to indicate if the bypass and drive would run the motor in the opposite direction, this feature shall be enabled by default The bypass shall include a supervisory control mode that monitors the value of the drive’s analog input (feedback). This feedback value is used to control the bypass contactor on/off state. The supervisory mode shall allow the user to maintain hysteresis control over applications such as cooling towers and booster pumps. Selectable Class 10, 20, or 30 electronic motor overload protection shall be included in both drive and bypass mode. The drive and bypass shall be designed to operate as an integrated system when in Override mode. Whether operating in drive or bypass mode, the low priority safeties will be ignored, and high priority safeties will be followed. External start/stop commands will be ignored. There shall be four selectable Override modes: Bypass only, with two smoke control modes: Fixed pre-configuration of digital inputs Configurable high/low priority safeties and faults, to allow configuration to meet needs of local Authority Having Jurisdiction. Drive only Drive then transfer to bypass, in the event of a drive fault Force to Stop Before the bypass circuit can be tested in commissioning, the drive must start the motor to check for shorts and ground faults Network communications – the bypass shall include BACnet MS/TP, ▇▇▇▇▇▇, and ▇▇▇▇▇▇▇ Controls N2 as standard. The bypass BACnet implementation shall be BTL Listed to Revision 14 or later. Optional communication cards for BACnet/IP, LonWorks, Profibus, Profinet, Ethernet/IP, Modbus TCP, and DeviceNet shall be available. The bypass relay output status, digital input status, warning and fault information can be monitored over the network. Status information shall be monitored, including; operating mode (drive vs bypass), current drawn in bypass mode, broken belt, and phase-to-phase voltage. The bypass start/stop command, force to bypass command, and relay outputs shall be capable of being controlled over the network.