Our view of limit switch for hoist and crane

 We must check the limit switches for each crane and hoist at the beginning.
 Lots of people are mistake in understanding the time limit for checking limit switches. even more, Many people think the limit switches are not needed and unnecessary to check. They think they will destroy the machine's original appearance and lose their ability to work once the limit switches have been checked, But the main reason for checking hoists and crane is the fear of failure, so people put the cart before the horse. What's the time limit to check limit switch of crane hoists? The most correct frequency is to check every shift and unnecessary to check every day. It is essential to check once in shifts---Every time you check in a shift, you can avoid some of the changes in the facilities, since the workers in the shift are different every day and they don't know what happened to yesterday's facilities, Normally they are won't repair previous day's problems.

 Does the limit switch need to be loaded in the test? The answer is no. When I got the news, I was visiting a client, this is an idea he put forward to me. Under load, no crane should be inspected, including limit switches. In fact, even during the testing process, professional crane personnel are required to complete the inspection. It is not advisable to check other parts at will. 

 Some companies directly let the operator jump over the limit switch when checking since they worry the limit switch is jammed or does not work during the inspection process, We should make a decision. Check the limit switch and prevent it from happening every time. you can move the load to the limit and lift it at a low speed or a single speed (if you have it) and then jogging If you don't want to check the limit switch many times, The pendant enables the load block to be incorporated into the limit switch, which is also a method. 

 I personally advise not to use fast speed when it is included in the load block, although many of the manuals suggest, but that is the case of a company with a senior operator. you can slowly drag it to the limit switch When you do it yourself. But you need to make sure that the load block may not stop at the same point. the greater the possibility that it will enter the limit switch when you slowly operate. This principle is like a decelerating vehicle. The faster you run, the longer the deceleration time is, so you need to take care of it slowly.

The second serious mistake is the use of a limit switch on the operating equipment, which is recommended in many professional manuals, I still have to correct this mistake after communicating with many customers, It is not to say that a limit switch can not be used on the operating equipment, but the limit switch should not be used every time the crane is operated. Many applications need the load block to reach its upper limit In order to get the highest height from the load hook, but I do not recommend unreserved use of the limit switch unless your crane is used. There are two limit switches on it. because it is only a safety device design, The limit switch does not operate continuously in the engineering of the device. Most of them are made of plastic and can not withstand too much wear. Repeated use can reduce the life of limit switches. You should ask if your bridge crane contractor has installed two limit switches on the machine when using a limit switch, and whether the limit switch can be used as an operating device.