High Leg Delta Motor Wiring

It is used when both single and three phase power is desired to be supplied from a three phase transformer or transformer bank.

High leg delta motor wiring. This reduces the wire cost and often simplifies manufacturing. If you look on the side of your motor there are often wiring instructions sometimes they are inside the wiring box. Panelboards since 1975 panelboards supplied by a 4 wire delta connected 3 phase system must have the high leg conductor terminate to the b phase of a panelboard 408 3. An engineer for a major motor manufacturer recently told me it is a juggling act between the number of turns number of circuits and the wire size three lead motors the stator windings of a three lead motor may be connected as either delta or wye see figure 1.

Many motors can be wired for a high and low voltage and for either delta or wye sometimes called y or star wiring. A change to the 2008 nec now allows the high leg of a four wire three phase delta service to be labeled as the c phase instead of the b phase. Wire a three phase motor in either a wye configuration or a delta configuration in high or low voltage using a nine lead set up. Examine the motor nameplate for wiring information.

A three phase motor is more efficient than a single phase motor because of the peculiarities of alternating current ac. Wire the motor for the appropriate voltage to which you are connecting the motor. A wiring diagram is a simplified conventional photographic depiction of an electrical circuit. The high leg conductor is also called the wild leg stinger leg or bastard leg other important nec rules relating to the high leg are as follows.

The nec code requires that the high leg be identified by an orange color it was often referred to as a red leg delta or by other effective means and is usually the b phase. The current of line 1 can be found by determining the vector difference between i r and i b and we can do that by increasing the i b vector in reverse so that i r and i b makes a parallelogram. High leg delta also known as wild leg stinger leg bastard leg high leg orange leg red leg dog leg delta is a type of electrical service connection for three phase electric power installations. The diagonal of that parallelogram shows the vector difference of i r and i b which is equal to current in line 1 i 1.

The nameplate will specify the motor voltages and may give specific wiring information. Collection of wye start delta run motor wiring diagram.