Introduction：
With the continuous development of cranes, it is difficult for traditional control technology to meet the increasingly high speed regulation and control requirements of cranes. Today, with the rapid development of electronic technology, the combination of crane and electronic technology is becoming more and more close, and the AC variable frequency speed control device replaces the traditional motor rotor series resistance speed control method. Among many AC variable frequency speed control devices, D32 frequency converter has made it widely used in various applications due to its stability of performance, richness of option expansion functions, flexibility of programming environment, excellent torque characteristics and adaptability to use in different occasions. Inverter occupies a very important position in the high-end market.
Features：
D32 is a wall-mounted inverter, the power range is 0.75KW-500KW, the voltage level of the incoming line voltage is 380V-480V, and the control method is vector control without speed sensor. D32 has a wealth of substations, including 8 digital inputs (LI1-LI8), 2 analog inputs (AI), 2 relay outputs (TA), 2 analog outputs (AO), 5V auxiliary power supply for analog power supply Fixed input, 24V auxiliary power supply is used for digital input, all LI/TA, AI/AO can be freely programmed to define functions.
MODBUS interface is standard configuration of D32, no option is required. The D32 can be connected to higher-level automation systems via MODBUS.
Advantage：
With excellent low-frequency torque characteristics, it can provide 0.5Hz 150% of the rated torque to ensure the smooth start of the variable frequency crane.
Reliable brake logic control, the brake time is adjustable, while ensuring that the hook does not slip, it also avoids the large inrush current of the motor.
The acceleration and deceleration process is in accordance with the S-curve mode, which increases the stability of the work, reduces the mechanical impact, and prolongs the service life of the equipment.
The starting current is small, the current impact on the power grid is small, the waste of power supply is greatly reduced, and the energy saving effect is obvious.
Complete protection function, improve safety factor and facilitate inspection and maintenance.
It has strong environmental adaptability, and the completely independent air duct design can greatly improve the resistance to harsh environments such as oil pollution, dust and damp heat.
System Introduction：
In this system, 4 sets of 7.5KW motors are driven by a D32 45KW inverter to realize the cart control of the gantry crane. D32 can provide complete brake opening logic control, high and low speed switching control, multi-motor parallel vector control, adjustable braking voltage control, high frequency field weakening operation control and other functions, so as to achieve perfect control of gantry cranes.
Technical Parameter：
| Inverter technical parameters | Device configuration | |
 Model: D32 | Output current: 92A | One D32 inverter |
| Input voltage: 3-phase, 380-480V | Frequency range: 0-400Hz | 7.5kW motor and load |
| Input frequency: 50/60Hz ±5% | Overload capacity: 150%, 60 seconds | Brake unit |
| Output power: 45KW | Ambient temperature: -10-40°C | Braking resistor |
| Output voltage: 0-480V (the maximum value is determined by the input voltage) | Protection level: IP20 | Other equipment such as reducer |
On Site Usage：
According to the on-site space situation, a D32 series inverter is installed in the control cabinet, and the inverter installation and on-site motor are as shown in the figure
Running Result：
The gantry crane control system using D32 inverter has been put into operation for more than three years, and has achieved good economic and social benefits:
* The control device operates reliably, has good environmental adaptability, can resist harsh environments such as oil pollution, dust and damp heat, and has a low failure rate;
*Excellent current limiting characteristics, strong overload capacity, can effectively reduce frequency conversion overload, overcurrent protection, and maximize production continuity;
* The starting and running process is smooth and efficient, safe and reliable.
Customer Benefits：
The inverter and crane operate stably, greatly reducing maintenance costs;
The comprehensive protection function of the inverter ensures maximum production continuity;
High and low speed switching control, high efficiency;
The brake control is realized by the frequency converter, and the safety is good.