Single-phase motor malfunction causes and prevention measures have those?
1, the correct selection of the capacity of the melt in the melt rated current choices of the formula is: rated current = K×
The rated current of the motor (1) fuse of large heat capacity,
There is packing type)
Can choose 1 K values.
5 ~ 2.
2 small heat capacity fuse can choose 4 ~ 6 K values.
For motor with load is different, also corresponding different K values, such as motor directly drives the fan, the K value can choose a few bigger, such as the load of the motor is not big, can choose smaller K values, depending on the motor with the load.
In addition, the melt of fuse and fuse holder must contact between good, otherwise it will cause fever contact, make the melt non fault caused by external heat fusing.
In the process of installation of motor, should adopt the appropriate connection mode and correct maintenance methods.
(1) check and adjust the contact pressure between melt and melt.
For the connection of copper and aluminum, as far as possible use of copper aluminum transition joints, such as no copper aluminum joints, can hang in the copper joint tin to connect.
2 for inserting fuse capacity is bigger, in the connection can be padded thin plate (
So that the effect will be better.
Wiring to avoid damage when the fuse, tighten wants moderate, wiring place to add spring washer.
2, fuse fusing: fuse non fault fuse can be avoided, not unilateral thought in can hide under the condition of motor starting current, the capacity of the melt as far as possible choose smaller, so that can protect the motor.
We want to be clear that fuse can only protect motor single-phase grounding and interphase short circuit accident, it must not be as the motor overload protection.
(1) failure fusing: is mainly due to the motor main circuit and single-phase grounding or short circuit and cause fuse fusing.
Precaution: choice to adapt to the surrounding environment condition of the motor and the correct installation of low voltage electrical appliances and circuit, and will be checked regularly, strengthen the daily maintenance work, timely eliminate all sorts of hidden dangers.
2 non fault characteristics: mainly to incorrect melt capacity, small volume, when to start the motor, the starting current impact, fuse fusing.
3, the main circuit is easy to appear the fault of a.
Improper installation, cause lead wire or wires broken by external force damage phase.
Preventive measures: in the process of wire and cable construction, to strictly implement & other;
Specification & throughout;
Strict and careful earnest, civilization construction.
Contacts of contactor of poor contact.
The main reason is: incorrect contactor, contactor arcing ability of small, make action contact together, three-phase contact action is not synchronized, due to lack of phase operation.
Precaution: choose to suit the contactor.
Electrical components are to be of poor quality, capacity of less than nominal capacity, contact damage, abnormal phenomenon such as death.
Precaution: select suitable components, before installation should be careful check.
The motor itself quality is bad, bad welding or desoldering coil winding;
Bad lead contact with the coil.
Precaution: choose better quality motor.
Not regular check, contactor contactor badly worn, uneven surface, make the contact pressure deficiencies caused by lack of phase operation.
Precautions: according to the actual situation, determine reasonable inspection maintenance cycle, carries on the strict and careful maintenance work in earnest.
Incorrect thermal relay, thermal relay the bimetallic strip of burn out, due to lack of phase operation.
Precaution: select the appropriate thermal relay, try to avoid overload phenomenon.
Use of conditions such as moisture, vibration, corrosive gas and poor heat dissipation condition, caused by contact oxidation damage or wiring, poor contact caused by lack of phase operation.
Precaution: choose to meet the environmental requirements of electrical components, protective measures should be properly, forced to improve the surrounding environment, regular replacement of components.