The crane control voltage refers to the voltage level used to operate the crane’s electrical control system (such as contactors, relays, PLCS, control buttons, limit switches, etc.). Its selection must comply with safety standards, equipment reliability, and the requirements of the applicable environment.
According to the provisions of the Chinese crane national standards, the control voltage of cranes includes general control voltage, DC control voltage, and power supply voltage for intelligent components. Generally, 24V, 36V, and 48V are the commonly used crane control voltages. Suppose the crane is equipped with a frequency converter. In that case, special attention should also be paid, as the frequency converter mostly adopts a three-phase AC power supply voltage with a higher safety level, and the intelligent control voltage inside the machine is usually a 48V DC voltage.
The stability of the crane control voltage is also important, especially in the troubleshooting of the crane. Any sudden changes need to be immediately investigated for their causes. The commonly used fluctuation range is limited to ± 10%. For instance, the fluctuation range of a 48V control voltage is between 43.2V and 52.8V. Crane control voltages exceeding this fluctuation range may affect the abnormal operation of the crane or cause malfunctions.
Below the safe voltage threshold: 48V falls within the safe voltage range (generally, 60V and below are considered safe voltages). Compared with high-voltage systems (such as 220V or 380V), it can significantly reduce the risk of electric shock and is suitable for harsh industrial environments such as dampness and dust.
Reduce arc risk: Low voltage generates less arc energy when there is a switch or line failure, reducing the possibility of fire and equipment damage.
Reducing energy consumption: Compared with traditional high-voltage control circuits, the 48V system has a smaller current (power = voltage × current), and the line loss (I²R) is significantly reduced, making it particularly suitable for crane operating conditions with frequent starts and stops.
Compatible with high-efficiency power supplies: The 48V system can be adapted to high-efficiency switching power supplies or battery packs (such as lithium batteries), and supports energy recovery technology to further enhance energy efficiency.
Electronic device-friendly: Modern control devices such as PLCS, sensors, and frequency converters typically support 24V/48V DC power supply. 48V can be directly matched, reducing voltage conversion links and enhancing system reliability.
Strong anti-interference ability: Compared with low voltage (such as 24V), 48V has less signal attenuation during long-distance transmission and stronger anti-electromagnetic interference ability, making it suitable for decentralized control of large cranes.
Low cable cost: Under the same power, 48V has a smaller current than 24V, allowing for the selection of thinner cables, which saves materials and installation costs.
Easy maintenance: The low-voltage system does not require high-voltage insulation protection, and the training costs for maintenance personnel and equipment maintenance are lower.
New energy trend: 48V is a common voltage for industrial energy storage and hybrid power systems (such as AGVs and electric forklifts), facilitating the integration of cranes with new energy technologies (such as battery packs and super capacitors).
Intelligent expansion: Provide stable low-voltage power support for Internet of Things (IoT) modules, remote monitoring, etc.
GB/T3811-2008 7.2.1.2 stipulates that “ Under normal working conditions, the voltage fluctuation of the power supply system at the feeder connection point of lifting machinery should not exceed ±10% of the rated value. ”
5.9.1.5 of GB/T 14405-2011 “General Bridge Cranes ” stipulates that “When button box control is adopted, the control voltage should not exceed 50V”.
IEC 60038 classifies voltages less than 50V into 6V, 12V, 24V, 36V and 48V.
The control voltages of crane electrical components such as contactors are also classified as 24V, 36V, and 48V.
In conclusion, the application of national standards is conducive to improving the production quality and usage safety of cranes. The accuracy, rigor, and precision of the national standards for crane control voltage indicators must be fully emphasized to ensure the safety of crane usage.
Henan Dejun crane adopts 48V as the standard control voltage configuration, which not only meets the requirements of national standards but also enhances the working stability of electrical components. If you have any questions, please feel free to contact us.
