We sold a control unit of the magnetic beam to a large customer abroad and I want to share my experiences with it. After all, those units control the operation of the magnetic lifting beam.
So at its simplest it switches the magnets on and off. Sounds simple. But, of course, there are always other variables in the equation, and perhaps the most important variable is that the magnets operate on direct current when the mains network is supplied with alternating current. And when the voltage from the mains is 400 V, the magnets typically operate at 110 V and sometimes 220 V. That is, the control panel needs a transformer to change the magnitude and type of voltage.
Because magnetic lifting beams often lift steel plates from a bundle and the lifting capacity of the magnet is twice the lifting capacity for safety reasons, several plates can be lifted as a result, even if the aim is to lift only one plate. Therefore, a power adjusting feature must be added to the control unit. Preferably adjusting can be done in advance as a preselection. Suitable setting is known from experience so that a plate of a certain thickness requires a certain lifting power. Or at least when lift has been done and excess plates have been gripped than intended, then the extra plates can be dropped off. In this case, it must be possible to reduce the power of the magnets “on the fly”, causing the plates to fall one by one. This procedure is called “tipping” in professional slang. The tipping is carried out by pressing two buttons on the crane’s radio control, when the power of the magnets begins to decrease linearly as a function of time. And when the buttons are released, the magnets return full power.
With current technology, adjusting the AC power is easy with the help of a frequency converter. When the AC frequency is changed, the power changes in the same proportion. But power control of a DC device is much more complicated. Even so inconvenient that “traditional” control cabinet manufacturers do not start manufacturing such equipment.
When the life cycle of the old control unit has expired, the unit must be replaced with a new one for fire and other safety reasons. Well defined, the new control panel will be exactly the same as the old one, but if you are not careful in defining the features, there may be surprises in the commissioning. With a minimal time window for deployment, even small time-consuming problems can be nerve-wracking. The factories are pushed to make the operation run as soon as possible and the equipment supplier has to work under high pressure. Safety issues cannot be compromised, neither in terms of the operation of the equipment, nor in terms of installation safety, nor in terms of the operation of the control panel.
If you have the opportunity to participate in the commissioning of the device you have sold, then seize the opportunity. In the customer’s environment, you will really realize how important it is that the device you sell meets the customer’s expectations.