Semi-Hermetic Big 4 Redesign SB-8
Semi-Hermetic Big 4 Redesign SB-8
Semi-Hermetic Big 4 Redesign SB-8
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<strong>SB</strong>-88JUL97<strong>Semi</strong>-<strong>Hermetic</strong> <strong>Big</strong> 4 <strong>Redesign</strong>The <strong>Big</strong>4 compressor line is undergoing a redesign to the motor and motor housing which will change thedimensional outline of the semi-hermetic compressor line.At this time the model numbering system will change. Letters indicating design level will allow for easieridentification of the different styles of machines:• “B” version is the old semi-hermetic built from 1977 to 1997• “C” version is the new semi-hermetic• Direct-drive <strong>Big</strong>4’s will have no design changes, however they will reflect the new model numberingsystem and remain at the “B” versionSee attached sheets for an explanation of nomenclature and some sample model number cross references.“C” version <strong>Big</strong>4 motor housings will be standardized on one size, long enough to encompass all motor sizes.This affects all but the current 50 HP models which will have the same overall dimensions (the difference inmotor housing length is approximately 1 5/8 inches). See attached dimensional drawing for details. Theredesign will allow for:• 60 hp, 111 CFM model for high temperature applications on 50 and 60 Hz—Model number 611BHF• Current suction filter design to be replaced by an easily serviceable suction strainer• New higher efficiency motors.Remanufactured (RMF) compressors for replacement of compressors manufactured prior to the “C” versioncan be supplied with the old-style motor housings. This will allow older compressors to be changed-out withoutany piping changes.Motor Protector: <strong>Big</strong>4 motors will change to TI sensors and thermal protection modules (HCI P/N 055970A1)replacing Robertshaw protection modules (HCI P/N CNT138). See Service Bulletin <strong>SB</strong>-5 for details. “C”version compressors with this new style of sensor will be completely phased-in this year.Locked Rotor Amps: Because of the motor redesign, the locked rotor values have changed. Running ampswill be slightly lower. See attached sheet for new locked rotor values.Page 1 of 5
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<strong>SB</strong>-88JUL97The “50 Hz only” restriction was a function of the compressor operating range, not the motor. The motor andcontrols can safely operate at 60 Hz, just not over the “normal” operating range of a “High Temp” machine.For consistency with the rest of the model numbers, it was decided to change the voltage designation to the “50and 60 Hz” codes for the new model numbering system. Therefore, remanufactured “B” version compressorswill be stamped with the appropriate 50/60 Hz codes.Example: 611BHFUBRMFBJ6C (NEW SYSTEM)Motor Voltage Code: BJ = 460-3-60 and 400-3-50Control Voltage Code: C = 115-50 and 115-60 (J = 230-50 and 230-60)Page 4 of 5
<strong>SB</strong>-88JUL97The new TI sensors will be phased-in by the end of the year. We will be shipping C version <strong>Big</strong>4’s with eitherRobertshaw or TI as the current stock of motors is used up. A code in the serial number will distinguish betweenthe two types of sensors.This is fine for new compressors. However, when replacement compressors are ordered, if the serial number isnot given, there is no way to distinguish between models.The solution can be to include the thermal protection module (either Robertshaw or TI, whichever motor thecompressor had in it) in the BOM or as an automatic line item.Page 5 of 5
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