How many channels should a crane remote control have?
Channel count equals the number of independent movements: 2 on a fixed hoist, 4 on a rail crane, 6 on an overhead crane. Auxiliary functions take channels too.
The channel count determines how many independent movements the remote control can drive. Opposite directions such as up/down work bidirectionally on a single channel, so what matters is the number of movements, not the number of directions. In practice 2 channels are typical for a fixed hoist, 4 for a crane travelling on a rail and 6 for an overhead crane.
Typical channel count by machine type
- 2 channels: fixed hoist, balcony crane (up, down)
- 4 channels: crane travelling on a rail (up, down, forward, backward)
- 6 channels: overhead crane (hoisting, long travel, cross travel)
Verify this list not by looking at the name of the machine but by opening the panel cover and counting the contactor groups. However many separate contactor pairs there are, that is the number of movements the remote control has to cover; the description in the machine catalogue is often out of date. The situations that call for four channels and the applications where six channels are used are covered separately.
Three situations that push the count up
These three situations add to the number you arrive at on first inspection:
- Two-speed crane: if the slow and the fast step are driven by separate commands, hoisting on its own uses up two steps.
- Auxiliary functions: horn, brake release, lighting, magnet or bucket door. These are not movements but they do consume channels.
- A second hoist: if there are two hoists on the same bridge, each one wants its own channel.
To make the count concrete: on a rail-travelling crane with a single hoist and a horn added later, hoisting, travelling and the horn are each counted separately. Dropping an auxiliary function from the list by saying "we will not use it anyway" is the most frequent reason for changing the receiver six months later. Draw the list up together with the operator; a habit of use that the person who built the panel does not know about usually comes out of them.
One channel more than you need
Since you may later want to add a horn, a brake or lighting, buying one channel more than you need is cheaper than replacing the remote control completely. At the moment of ordering the difference is a single model step; enlarging it afterwards means redoing the receiver, the transmitter and the wiring inside the panel as well. Whether the channel count can be increased later depends on the structure of the set, and in most cases the answer is replacing the receiver.
What the channel count does not solve
The channel determines which command the remote control will send; it does not determine how much current that command will carry. Even if you have chosen the right channel count, if you connect the relay contact directly to a motor it cannot carry, the output is still strained. In the same way, adding channels does not gain range, does not raise the ingress protection rating and does not produce a safety function: the limit switch chain and the emergency stop are built on the panel side, independently of the channel count.
Add-ons such as a magnet, a vacuum lifter or an electric bucket, beyond consuming a channel, want a supply circuit of their own. The remote control only gives them a command, it does not carry the power; the supply, the protection and, where required, the arrangement that holds during a power cut are built separately. The same limit applies to brake release.
Final check before ordering
Count the contactor pairs, add the auxiliary functions to the list, put one channel on top. When you order with the resulting number, put which channel will go to which motor down on paper and mark the same numbering both on the transmitter and on the terminal label. During commissioning, verify each channel one by one, first with no load and then under load.
When you add channels, take into account that the number of buttons on the transmitter goes up as well. On a remote control operated with gloved hands, the denser the buttons the higher the chance of pressing the wrong one; so adding a function to the list that will not really be used is not free either. The target is as many channels as you need, plus a single spare on top.
The full topic: Wireless Crane Remote Control Selection Guide