Danfoss Performer SH090 Selection & Application Manuallines

Also see for Performer SH090: Instructions Instructions Application guidelines Application guidelines Application guidelines

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Danfoss Performer SH090 Selection & Application Manuallines Manual pdf 27 page image

APPLICATION GUIDELINESFRCC.PC.007.B5.02 27Cycle rate limitA low-pressure (LP) safety switch must be used.Deep vacuum operations of a scroll compressorcan cause internal electrical arcing and scroll in-stability. Performer SH Scroll compressors exhibithigh volumetric efficiency and may draw very lowvacuum levels, which could induce such a prob-lem. The minimum low-pressure safety switch(loss-of-charge safety switch) setting is given inthe following table. For systems without pump-down, the LP safety switch must either be a man-ual lockout device or an automatic switch wiredinto an electrical lockout circuit. The LP switchtolerance must not allow for vacuum operationsof the compressor. LP switch settings for pump-down cycles with automatic reset are also listedin the table below.Low pressureO PERATING CONDITIONSDanfoss recommends a restart delay timer to limitcompressor cycling. The timer prevents reversecompressor rotation, which may occur duringbrief power interruptions.The system must be designed in a way that guar-antees a minimum compressor running time of 2minutes so as to provide for sufficient motor cool-ing after start-up along with proper oil return.Note that the oil return may vary since it dependsupon system design.There must be no more than 12 starts per hour, anumber higher than 12 reduces the service life ofthe motor-compressor unit. A three-minute (180-sec) time out is recommended.Note that these two different low pressure switch-es also require different settings. The low pressurepump down switch setting must always be withinthe operating envelope, for example 2.3 bar forR410A. The compressor can be operated full timeunder such condition. The minimum low pressuresafety switch setting may be outside the normaloperating envelope and should only be reachedin exceptional (emergency) situations, for exam-ple 1.5 bar for R410A.Please contact Danfoss Technical Support for any deviation from this guidelines.T TTHTHKAA1 A2 A3A1180 sA2 KA~~Pressure settings R410AWorking pressure range high side bar (g) 13.5 - 44.5Working pressure range low side bar (g) 2.3 - 11.6Maximum high pressure safety switch setting bar (g) 45Minimum low pressure safety switch setting * bar (g) 1.5Minimum low pressure pump-down switch setting ** bar (g) 2.3* LP safety switch shall never be bypassed and shall have no time delay.** Recommended pump-down switch settings: 1.5 bar below nominal evap. pressure with minimum of 2.3 bar(g)