Full Description Preface This is the first edition of CSA C838, Energy efficiency test methods for three-phase variable frequency drive systems. Variable frequency drives (VFDs) have the ability to vary the speed of the motor from 0% to its full range at an infinite range of torque. This Standard defines a testing methodology that provides performance information that can assist with the process of selecting a VFD adequate to the motor driven process. It is estimated that 30% of all industrial motor systems can potentially be improved by the use of VFDs to control speed and torque, resulting in large energy savings. CSA acknowledges that the development of this Standard was made possible, in part, by the financial support of BC Hydro, Efficiency Nova Scotia, Hydro-Quebec, Manitoba Hydro, Natural Resources Canada (NRCan), the Ontario Ministry of Energy (OME), the Ontario Power Authority (OPA), and the Canadian Electricity Association (CEA). Scope 1.1 This Standard establishes the testing procedure for determining efficiencies under varying loads and speeds for three-phase output variable frequency drives (VFDs) with rated voltage up to 750 V. This test procedure is limited to a combination of one motor with one drive. This Standard applies to voltage source inverter (VSI) pulse-width modulated (PWM) drives for squirrel-cage induction motors and other three-phase VFD technologies commonly used with permanent magnet and reluctance motor-drive systems. This Standard does not cover VFDs with a rated voltage rating greater than 750 V. Ancillary equipment are not to be included unless they are contained within the confines of the input and output terminals of the VFD device, or a mandatory requirement for the operation of the VFD. Note: Small motors supplied with special purpose VFDs of the single- phase type are covered by CSA C747. 1.2 In CSA standards, \"shall\" is used to express a requirement, i.e., a provision that the user is obliged to satisfy in order to comply with the standard; \"should\" is used to express a recommendation or that which is advised but not required; and \"may\" is used to express an option or that which is permissible within the limits of the standard. Notes accompanying clauses do not include requirements or alternative requirements; the purpose of a note accompanying a clause is to separate from the text explanatory or informative material. Notes to tables and figures are considered part of the table or figure and may be written as requirements. Annexes are designated normative (mandatory) or informative (non- mandatory) to define their application.