Common failures of frequency converters are overvoltage, overload, overcurrent and overheating. Which generally caused by improper use and the operating environment. Variable frequency drive belongs to electronic products; while the electronic products composed of many components, they will not typically work if any of those components go wrong. Also, electronic products have a particular service life. The ageing of the product will be more evident with the use of time.
Variable frequency drive service life and use environment
According to the tax duty calculation regulation for fixed asset depreciation, the lowest fixed number of electronic equipment is three years. Many people buy a mobile phone and changed to a new one after two or three years of use, even it's still working fine. But the frequency that TV, computer refrigerators, and air conditioning these home appliances go out is relatively low. Design theory life is highest can reach 15 years, even though most people won't use it for a long time. The variable frequency drive belongs to industrial electronic equipment, and its durability will be higher. It is common for some factories to use some variable frequency drives for more than ten years. Some Japanese or German VFDs even use for more than 20 years. Of course, during this period, the bus capacitor is generally changed. As long as the workshop environment is good, and the maintenance is in place, the variable frequency drive's overall life is much longer than that of household appliances.
-Corrosive gas and static dust
Some chemical and plastic factories have corrosive gas and static dust electricity, and the variable frequency drives do not have any protection. Nor does it buy a professional application for the variable frequency drives. It is directly installed in the workshop, without distinct separation, and often breaks down within a year and a half. Dust and corrosion will directly harm the circuit board and the welding joint itself, and the static electricity or poor insulation will now let the electronic components breakdown and damage.
Some types of equipment have significant vibration, such as a punch press. When using a variable frequency drive with improper installation under this occasion. VFDs will also follow the jolt vibration. This will lead to variable frequency drives to lose line joints and damages after some time.
Some places are relatively humid, such as some water supply and drainage workshops, or some humidifying areas, or in the outdoor environment, humid and high temperature, which may cause the breakdown of insulation of the variable frequency drive. So, if you want to avoid damages and extend its service life, the variable frequency drives should be installed in a separate electrical cabinet workshop conditionally, paired with air conditioning and exhaust fans, to reduce the probability of damage to the variable frequency drives
Incorrect selection or improper use
The variable-frequency drives used to drive the motor to work. It is a power source that changes the frequency and voltage. It needs to choose the right product according to the engine and the load situation. In addition to the generality of early variable frequency drives, there are also fan pump type and vector type. With the increase of variable frequency drives, many particular variable frequency drives have developed according to the equipment, such as elevator VFDs, ball mill VFDs, spinning VFDs, etc. Suppose uses a specific variable frequency drive. In that case, it will, in theory, be more competent than the ordinary frequency converter for the corresponding load and can cope with the current user environment. It won't easily break down.
And in some cases, the need to frequently start variable frequency drives, so it needs to increase the capacity to use, avoid damage caused by excessive temperature, or increase the outside of the brake unit and brake resistance to prevent the impact of long-term braking. Some occasions do not need a very short acceleration, and deceleration time should be appropriate to adjust a little longer. Some loads need to operate at low speed. The variable frequency drive needs to avoid working in the low-frequency band. Variable frequency drives actual working frequency by increasing the speed change ratio, which can also prolong the variable frequency drive's service life.
A variable frequency drive needs to consider good grounding and appropriate lightning protection devices in some areas with frequent lightning. The damage of variable frequency drive by lightning is not uncommon.
In some areas, Variable frequency drives should install the addition of line reactors, bus reactors, and output filters because of the grid's significant voltage fluctuation or the relative distance of the load.
Quality problems of VFD itself
Because of the accumulation of many years of process data and more reliable components, a good brand variable frequency drives the overall probability of damage is lower than some small brands. Because of a rigorous quality management system, the service life will be longer than the small brand. The voltage withstands value of the modules used will be a little higher for a good brand variable frequency drive, and the current overload capacity will be more substantial. Electrolytic capacitors and other parts that are easy to be ageing will also be of relatively better quality.
Source from Okmarts
Discuss challenges in energy and automation with 30,000+ experts and peers.
Find answers in 10,000+ support articles to help solve your product and business challenges.
Find peer based solutions to your questions. Provide answers for fellow community members!