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I have a 460 volt 3 phase feed to our bldg. We had a single phase condition to our bldg and we had quite a few 120 coils on 460 volt 3 phase VFD contactors short out Do not know why help?
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∙ 12y ago
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∙ 12y ago
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What are the main Components of control panel?
some of the main components in the control panel are single phase preventers,contactors-are of two types they are power contactors and control contactors,relays, overload relays,transformers for the equipment and for cooling purpose,etc
What is the typical voltage of a control transformer for a three phase 480 volt starter?
Most 3 Phase 480V Starters are controlled by 120VAC. This is because the coils on the contactors (starters) are 120VAC. Just ensure the voltage matches the coil.
What are the basic construction of a single phase transformer?
two coils and a metal plates
What is hinky pinky for a triple set of electrical contactors?
That would be: Three-phase relays
What devices are used to protect a three-phase motor and are placed on the bottom of contactors?
thermal overloads
Why is it called single phasing?
On a three phase system you have incorporated into it a potential of three single phase systems. A-B, B-C, C-A. Any two legs of a three phase system can be used as a single phase load. On a three phase system, be it a motor or a service, if one of the legs drops out for what ever reason, the remaining two legs are known as single phase. This is how the terminology became single phasing. As a side note a motor will run in a single phase condition, it just will not start. In motor control, a single phase condition is prevented by the use of overload heaters on all three voltage legs.
Assuming that the listed exception do not apply the NEC states that the minimum number of overload units required for a three-phase alternating current motor shall be?
Each leg of a three phase motor must have overload protection. There is no minimum. Older magnetic contactors used to only protect two legs but occasions arose out of this configuration that would cause the motor to single phase on an overload condition. The code was changed to stop this condition from happening so now all three legs must be protected.
Why does single coils always hum?
Humbuckers are called "Hum"-"buckers" for a reason- they are two single coils wired to achieve noise phase-cancelation. Single coils do not have this feature, but if you notice that if you have a 5-way selector switch and you use your KNECK and MIDDLE singlecoils on a Stratocaster (assuming you have a 3 singlecoil setup) or a MIDDLE and BRIDGE, there is no hum, because of this sample principle.
Is air conditioner works on 1 phase and how it works on 3 phase also?
If an air condition is single phase, then it can only be connected to a single phase source. Since any two legs of a three phase source are considered single phase, there is no conflict, except to note that the individual phases of the three phase source match the voltage requirement of the air conditioner.
What is the xo terminal on a transformer used for?
The XO denotes the joined secondary terminal connection of three single coils of a three phase transformer. It is the common return on any unbalanced current of a three phase system.
Can you use what was a 3 phase motor as a windmill that produces single phase power?
No. To generate an electrical voltage you have to move the flux of a magnet through a coil of wire or vice versa. In a three phase motor there is no magnetic flux in the armature to cut the stator coils.
Why motor burn at single phasing?
A 3-phase motor will not run on single-phase power or if one of the three phases is disconnected. If the motor is not running, there is no back-EMF generated in the coils, and they draw excessive current, thus overheating.
