Instructions 958-HCA32 Solid State Overload Relay with Phase Loss Protection Trip Curve “A” & “B” Class 958 May, 2000 Supersedes Issue of June, 1993 DESCRIPTION Class 958 overload relays are self-powered solid state overload relays i.e. they generate their own running power and do not need a separate source of 120V to power the circuit board. These overload relays provide excellent protection of hermetically sealed compressors and artificially cooled motors requiring ambient insensitivity and quick trip response. The trip curves (Fig. 1) have been custom tailored to provide proper overload protection on such loads without nuisance tripping. The overload also provides phase loss protection for the motor by tripping within 3 seconds when there is a complete loss of one phase of the three phase motor branch circuit. Each overload has a 2:1 current adjustment range with the adjustment dial reading out in motor must hold amps. Must trip amps are 112% of the must hold setting. In addition to the markings on the dial there are audibile clicks which allow for extremely fine tuning. Note that while thermal overloads require a heater selection based on a relatively wide range, these overloads have many clicks covering the same ampere range (Fig. 2). Hazardous voltage. Can cause death, serious personal injury, or property damage. Disconnect power before working on this equipment. Cat No “A”Trip Cat No “B”Trip Current Range (Amps) 958CA32A 958DA32A 958EA32A 958FA32A 958CA32B 958DA32B 958EA32B 958FA32B 33 - 66 50 - 100 75 - 150 90 - 180 Figure 2 Figure 1 (For Engineering Reference Only - Rev. D) Siemens Energy & Automation, Inc. 1000 McKee Street Batavia, Illinois 60510 Instructions 958-HCA32 Page 2 May, 2000 Supersedes June, 1993 INSTALLATION: There are mounting hole locations in the housing of the overload so that they may be directly attached to a mounting panel. All of the mounting locations should be used to prevent vibration and/or breakage of the housing during use. These overloads are not connected to the motor branch circuits in any way. Proper installation simply requires that the motor leads be passed through the “windows” in the overload relay (Fig. 3), and the normally closed contact be wired into the control circuit. A typical wiring diagram is shown in Figure 4. APPLICATIONS: Class 958 overload relays are suitable for use with 50 or 60 Hz motors and have an operating range from -22vF to +159vF (-30vC to 70vC). *The motor voltage can exceed 600 Volts, but the control circuit contact is rated NEMA A600 and NEMA P600 (10 Amps, 600 VAC maximum and 5 Amps, 600 VDC maximum). NOTE: * The 90 - 180 Amp overload has an operating temperature range of -22vF to 140vF (-30vC to 60vC) Figure 3 Figure 4 Dimensions Siemens Energy & Automation, Inc. 1000 McKee Street Batavia, Illinois 60510