U.S. Patent No. 5,705,989 Sensor Power H904/H934: Induced from monitored conductor; H720: 12 to 30 Vdc Insulation Class600 Vac RMS Frequency Range: H720 H904/H934 10 to 80 Hz; 20 to 34 Hz for on/off status, 34 to 75 Hz for belt loss indication On/Off status for Variable Frequency Drive (VFD) outputs 1 Temperature Range-15 to 60 °C (5 to 140 °F) Humidity Range10 to 90% RH non-condensing Off Delay (H904/H934)0 sec to 2 min. Accuracy (H720) 0.5% of 200 A (combined linearity, hysteresis, and repeatability) Hawkeye 720, 904 and 934 current monitoring devices provide unique solutions for accurately monitoring status of motors controlled by variable frequency drives. The microprocessor-based H904 and H934 store the sensed amperage values for normal operation at various frequency ranges in non-volatile memory. This information allows the device to distinguish between a reduced amp draw due to normal changes in the frequency and an abnormal amp drop due to belt loss or other mechanical failures. The relay on the H934 is isolated from the current switch, and all relay connections are externally accessible on the device. The H720 analog output corresponds to current in the monitored conductor from 10 to 80 Hz. DETECTS BELT LOSS/COUPLING SHEAR!DETECTS BELT LOSS/COUPLING SHEAR! Now you can easily detect when drive belts slip, break, or pump couplings shear. In fact, a typical HVAC motor that loses its load has a reduction of current draw of up to 50%. That’s why our sensors are the industry standard for status. Calibrated Trip Point OO Fan/pump On Loss of Belt/Coupling Shear Electrical Failure H934 H720H904 Also see H614. E150462 Note: Do not use the LED status indicators as evidence of applied voltage. 1. VFD systems generate fields that can disrupt electrical devices. Ensure that these fields are minimized and are not affecting the sensor. Maximize Reliability Minimize Installed Cost Terminal Block Wire Size24 to 14 AWG (0.2 to 2.1 mm 2 ) Terminal Block Torque3.5 to 4.4 in-lbs (0.4 to 0.5 N-m) WARRANTY Limited Warranty5 years AGENCY APPROVALS Agency Approvals UL 508 open device listing CAT III, Pollution Degree 2, basic insulation SPECIFICATIONS TM APPLICATIONS • Monitoring positive status on motors controlled by variable frequency drives • Replacing pressure switches • Measuring current and load trending Load side monitoring Suitable for llad side monitoring of VFDs (H720) Automatically compensates Automatically compensates for the effects of frequency and amperage changes in monitored conductor associated with VFDs (H901/934) Precise scaling Adjustable zero and span for precise scaling (H720) Nuisance reduction Provides a secondary setpoint option of 50% of the originally measured current (H901/934) 0.5% accuracy Accurate to 0.5% of full scale (H720) Rapid troubleshooting LED indicates normal and alarm conditions (H901/934) 800.354.8556 | +1 503.598.4564 | sales@veris.com | intl@veris.com | www.veris.com TM H720, H904 & H934 Variable Frequency Drive Monitoring and Control Current Monitoring | VFD Switches and Current Sensors HQ0001758.F 0117EXAMPLE LINEAR OUTPUT (H720) Scale software as shown Requires 12 to 30 Vdc for sensor power MODELAMPERAGE RANGESTATUS OUTPUT MIN. TRIP POINT RELAY TYPE HOUSING STATUS LED RELAY POWER LED UL H720 Lower limit: 0 A Upper limit: 20 to 200 A 4 to 20mAn/anoneSolid-core••• H904 3.5 to 135 A, 20 to 75 Hz Max. N.O. 0.1 A @ 30 Vac/dc 3.5 A or less none Split-core ••• H934 SPST, N.O. ••• * Terminal block may extend up to 1/8” over the height dimensions shown. 3.13" (80 mm) 0.33" (9 mm) 2.15" (55 mm) 3.0" (76 mm) 1.00" (26 mm) 0.7" (19 mm) Removable/Adjustable Mounting BracketRemovable Mounting Bracket Self-gripping Iris 1.0” (25 mm) 0.8” (21 mm) 1.1” (26 mm) 3.1”** (79 mm) 2.8” (70 mm) Ø 0.3” (8 mm) 1.4”* (36 mm) 2.5” (64 mm) 3.0” (76 mm) Bracket can be mounted on three sides for added installation flexibility. Note: For auto-calibrating model see H614. Note: The H904 is not intended for use in staged pump or variable inlet vane applications. Fan or Pump CONTROL Digital Input Motor VFD CONTACTOR Voltage input 250Ω = 1 to 5 Vdc 500Ω = 2 to 10 Vdc + – CONTROLLER Voltage Output SENSED AMPS 200 A 4 mA 0 A 20 mA SENSOR OUTPUT H934 Relay Contact Ratings Resistive - 5A @ 250 Vac, 30 Vdc Typical Coil Performance VoltageACDC 24V10 mA10 mA H720 Dimensional Drawing H904/934 Dimensional Drawing MONITORING FAN /PUMP MOTORS FOR POSITIVE PROOF OF FLOW Wiring Diagram ORDERING INFORMATION 800.354.8556 | +1 503.598.4564 | sales@veris.com | intl@veris.com | www.veris.com TM Current Monitoring | H904, H934 & H720 HQ0001758.F 0117Next >