Hi Sachin,

I guess the answer depends on the specific drive-motor combination that you are talking about. 

Manufacturers would obviously strive to meet specified standards to the best extent possible.

-Sanjay

Dear Sir,

As you know, there are two aspects of the power quality problem: one of them are the conditions imposed for the low voltage network supplier. These conditions (regarding different parameters of the power quality) are stipulated by national/regional standards (as example IEEE 519 std. in USA or EN 50160 in Europe). The conditions are imposed for voltage parameters.

Regarding the conditions to be complied by manufactured equipment (is the responsibility of manufacturer, because it’s a problem of equipment's emission), there are other standards, as example (regarding THD) IEC 61000-3-2 -Electromagnetic compatibility (EMC) - Part 3-2: Limits - Limits for harmonic current emissions (equipment input current ≤16 A per phase). The conditions are imposed for (absorbed) current.

So, there are not special requirements for the voltage which supply a certain/given equipment. But the user must know the conditions of the network where it will be connected, in order to choose an equipment with adequate electromagnetic immunity.

As mentioned above, IEEE 519-1992 and IEEE 519-2004 provide suggested limitations for THD in power systems. ICS 29-200 provide THD standards for Rectifiers, Converters, and Stabilized Power Supplies. Fourier analysis would be a common tool used for defining acceptable levels of Voltage harmonic distortion in VFDs based upon the feedback at the Point of Common Interconnect (PCC) as it relates to the power system. Without having modeled the type and quantity of the feedback at the PCC, it would be dangerous to specify the THD limits of the VFD for a given system.