Variable frequency drive system needs improve

As a sales engineer I am continuously confronted with what is the best solution for my customer's application. The truth of the matter, most customers can only discuss their current requirements and really can't project their future needs or the direction of the company. My approach with my customers is to keep it simple and flexible.

I suggest to use a 6 pulse drive and use a harmonic device as an adder. In today's world the variable frequency drive faces many potential problems. Power failures, lighting strikes, shorts, etc. If a VFD fails for any reason, a replacement VFD can be had at any local distributor within hours. If need be one could buy a different manufacturer's variable speed drive if the application is critical. At the same time if the external Harmonic device failed, the process would continue without stoppage. The only problem for a short period of time would be that there will be no harmonic mitigation. Recently I visited a company that ran for 3 months without the harmonic filter with no adverse effects. (The company forgot to turn on the breaker for the harmonic drive.) Manufacturers offer both active filters and passive filters to resolve harmonic problems. Having 2 pieces of equipment provides the customer more flexibility in adding additional VFDs or changing to larger drives in the future.