Power System

Depending on your local electrical code, if you need a grounded (earthed) system, you can use a 400V-Delta to 208/120V WYE transformer to feed a variable frequency drive (VFD), and then set it a 60Hz to supply 208V 60Hz to the motor. Although I do not normally recommend it, if it is appropriate for you to run the system ungrounded (unearthed), then you can feed the VFD with through a 400V-Delta to 230V-Delta transformer and then supply the motor with 230V 60Hz power from the VFD. (As with mos ...

In Europe we have a 1-phase 220v/240v power supply to home, which is ONE hot line, unlike America that have TWO hot lines (120v of each) into their homes which is therefore logically and technically a 2-phase power supply, even if they will admit the obvious.

There are two ways we can be feed our 1-phase supply from the pole mounted 3-phase 11kV line. The primary of that transformer can be feed from either one of the 3-phase lines, that would be 6.4kV to Earth, or feed from two of ...

Having the motor star point earthed won't have any effect on protecting the motor windings during a fault condition.

A power system must be referenced to earth at a single point, usually at the supply transformer or generator star point. Referencing the system to earth at multiple points on a distribution system, for example, at the star point on your motor (in addition to the supply transformer star point), would be bad practice as it could lead to the undesirable condition of cre ...

For an AC machine (induction OR synchronous), current required for a given load is dependent on applied voltage, overall efficiency, and power factor. With power factor at unity (1.00 per unit), current is at a minimum - but there is no appreciable amount of reactive power (either leading OR lagging).

Some machine designs have a "low" power factor, but that is typically because another performance parameter is being optimized (i.e. deemed more important to the user). For example - ...

From my view-point of a power system analyst, I see the following:
In industrial environments (LV and MV systems), the higher short-circuit level advantages are: less voltage drops due to transient loads (ex: motor starting across the line); less impact of harmonic loads (harmonic currents cannot cause too much variation on the harmonic voltage distortion where the short-circuit level is expected to be higher); less over voltages due to bolted ground faults. Disadvantages: higher incide ...