Motor soft starter in crane and its functions

Keyword:soft starter, thyristor   Time:2018-11-30 8:43:01

Motor soft starter and thyristor in crane 

Motor soft starter and thyristor in crane.png

When the soft starter begins the motor, the starting current of the motor increases gradually, and the thyristor conduction angle rises from zero to the set value. This is called no shock current.
The soft starter can introduce a closed loop current control, so that the motor can maintain a constant current during the starting process and ensure the stable starting of the motor. This is a constant current start.
The best starting current can be adjusted freely and continuously. This is the characteristic of the load condition and the relay protection.

Decompression start of motor and decompression start connection drawing.jpg

Decompression start of motor and decompression start connection drawing

Because the soft starter has many functions, it is superior to the star delta starter and the self coupling starter. It can realize man-machine conversation and operate by keyboard, computer or manual remote control. It's like a person's IQ, not only can achieve soft stop, but also has many protective functions. Because these new humanized equipment requirements are highly respected.
Soft start's characteristics
 a). It reduces the impact of mechanical impact on the load. The starting voltage of the motor can rise steadily at a constant slope, and the starting current is small, and there is no impact current on the power grid.
 b). The rising slope of the starting voltage can be adjusted to ensure the smoothness of the starting voltage. According to different loads, the starting voltage can be adjusted continuously in the range of 30%-70%.
 c). It can set startup times depending on the load.
 d). The soft starter also has thyristor short circuit overload protection, phase loss protection, overheating protection and other protection function. It can reduce the impact on the power grid and wear of machinery, reduce the maintenance of starting devices, and meet the needs of modern production.
 1.  Overload protection function
 The overload protection function is realized by adding overload current setting and  anti time control mode. When the motor is overloaded, turn off the thyristor and send out the alarm signal. The soft starter uses the current control loop to track and detect the current changes of the motor at any time.
 2.  Phase deficiency protection function
 The soft starter can detect the change of three-phase current at any time. Once the current is cut off, the phase loss protection response can be carried out, which is its working principle.
 3.  Overheat protection function
 The thermal relay inside the soft starter can detect the temperature of the thyristor radiator. When the radiator temperature exceeds the allowable value, the thyristor will automatically turn off and send out the alarm signal.
 4.  Other protection functions
 It can realize other kinds of chain protection in the system through the combination of electronic circuits.
 our bridge crane, Longmen crane, gantry crane, electric hoist and electric winch are developing well. And all the products of the motor are equipped with soft start. Ramhoist has a strong technical team. This team has been committed to upgrading the product technology. At present, the crane is at the forefront of technology. Please contact us when you need cranes and hoists.

Ramhoist News
  • No information
Ramhoist FAQ