Static Frequency Converters have both maximum kVA (Apparent Power) ratings and kW (Real Power) ratings – the difference between the two being commonly referred to as the Power Factor.n nIn general, when sizing a Frequency Converter, neither the kW nor kVA rating of a Frequency Converter should be exceeded. Equipment nameplate ratings are often stated in kVA, which makes it difficult to know the kilo-watt ratings. If using equipment nameplate ratings for sizing, a user might configure a system, which appears to be correctly sized based on kVA ratings, but actually exceeds the Frequency Converters kW rating. By sizing the kVA rating of a load to be no greater than 60% of the kVA rating of the Converter, it minimizes the risk of exceeding the watt rating of the Converter. Therefore, unless you have a high certainty of the Watt ratings of the loads, the safest approach, and widely considered to be the ‘best practice’, is to keep the sum of the load nameplate ratings below 60% of the converters kVA rating.n nWhere the load type is inductive in nature, such as motors (fans, pumps, etc), solenoids, and relays, it is essential that high inrush current and short-time overload factors are fully considered. With motors (without a soft start facility) typically drawing on start-up current 5 to 7 times the stated rating of the motor it is recommended that a Frequency Converter is selected that is at least 3 times the stated rated capacity of the load.