bybakersj05-20-201010:53 AM - edited 05-21-201009:38 AM
Non-linear loads Non-linear loads create harmonics and voltage distortion, degrading the performance of a generator set. The percentage of voltage distortion is especially critical in data center applications. A generator set's alternator must be properly sized to limit voltage distortion to an acceptable level. Some types of non-linear loads are:
Uninterruptible Power Supply (UPS)
Variable Frequency Drive Motors – VFD (60 Hz)
Variable Speed Drive Motors – VSD (50 Hz)
Filters & Pulse Rectifiers To offset the unfavorable effects of non-linear loads, consulting engineers can upsize the alternator or recommend a higher rated (thus more costly) generator set.
However, adding filters and/or increasing the pulse count of pulse rectifiers (e.g. 6 pulse to 12 pulse, 18 pulse or 24 pulse) on a generator set can reduce the harmful effects of non-linear loads. Alternator life can be extended by avoiding the overheating caused by distortion. Power quality can be maintained or improved. Taking those measures can allow for a smaller ekW/kVA rated generator set and reduce the initial purchase cost.
As a consulting/specifying engineer or a commissioning engineer, what are the applications or situations in which you recommend the use of filters or higher pulse rectifiers on a generator set?
What types/size of filters and/or pulse rectifiers do you recommend to balance the cost-benefit trade-off between the purchase price of a filter or pulse rectifier, and the opportunity to downsize the required ekW/kVA rating of the generator set?
What are some applications in which you have effectively reduced your customer's costs by using filters or pulse rectifiers?
Are there any problems you have encountered using filters and/or pulse rectifiers?
What are some rules of thumb you would advocate to a colleague who is faced with a customer site application where harmonics and voltage distortion are a concern?