valutazioni - 3, GPA: 4 ( )

Produttore : Omega Engineering File Size : 103.95 kb File Nome : Lingua di insegnamento:

• The conductors of the intrinsically safe circuit should be sealed in a rigid metal conduit at the point where the wiring enters the hazardous area. The wiring and sensor switch should be such that conductive dusts in the hazardous area will not close the circuit. • Hazardous area field wiring will store energy due to distributed capacitance and inductance in proportion to its length. It is therefore recommended that the characteristics of the cable be known and judged against the length of run and atmosphere of exposure. The following chart is presented as a guideline in determining the limits of reactance for signal loops in the hazardous area wiring for the intrinsically safe solid-state relays. WARNING Product must be maintained and installed in strict accordance with the National Electrical Code. Failure to observe this warning could result in serious injuries or damages. GROUP CAPACITANCE INDUCTANCE A & B 0.1 .F 3 mH C 0.2 .F 10mH D 0.3 .F 20mH Example: Typical values of capacitance for a twisted pair of copper wires is between 20 and 60 pF per foot. Using the maximum value of 60pF/ft, Groups A & B could have a run of 1500+ feet with safety. Inductance of a typical twisted pair is between 0.10 and 0.20 .H/ ft, thus making a cable run in this example essentially determined by the capacitance. Fig. 2. Connection Diagram: Model SBG41705 Hazardous LocationSensor Switch LOADVAC AC Load Latching Solid-State Relay SBG41705 On C Off Non-Hazardous Location Non-Intrinsically Earth Safe Wiring Ground (2 Places) Common Earth- Multiple Grounded Units Mounting Plate Intrinsically Safe Wiring Resistance to ground must be from bracket to earthing member to insure integrity of system. To Sensors (Must be below one ohm.) Note: All intrinsically safe wiring must be segregated from non-intrinsically safe wiring. Fig. 3. Multiple units grouped on a common, earth-grounded mounting plate. Mounting Intrinsically Safe Solid-State Relays #10 Screw #10 Lockwasher* #10 Lockwasher* Plate #10 Nut • Whenever possible, the actual measured parameters should be used in making the determination of allowable length. • Shielded cable is not required, but if used in the application, the shield must be returned to ground, the same point at mounting tab. *(Lockwashers to be internal or external tooth type) Fig. 4. Unit Mounting Detail • Non-intrinsically safe wiring cannot be run in conduit or open raceways together with intrinsically safe wiring.** • Refer to Fig 6 for detailed connection to terminal studs. All hardware, including terminal lugs, is supplied with unit. • Fusing of the solid-state relays to be in accordance with Fig. 1. Fuse F1 to be 6 amps slo-blo, 120 VAC for 120V line voltage; 250 VAC for 240 V application. **Note: All intrinsically safe wiring to intrinsically safe solid-state relays must be segregated from non-intrinsically safe wiring. Lockwasher* NutLockwasher* NutMountingScrew Plate Lockwasher* Terminal Lug Notes: 1. *(Lockwasher to be internal or externa...

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