The chain jamming of the electric chain hoist may be caused by the following reasons:

1. Long term lack of oiling: If the chain of the crane is not oiled for a long time, it will cause the chain to wear more severely, the surface of the chain to harden, the friction between the sprocket and the chain to increase, and ultimately lead to the chain getting stuck.

2. Abnormal wear of the chain: If the chain of the crane experiences abnormal wear, such as chain deformation or inconsistent distance between chain segments, it will cause the chain to malfunction and get stuck.

3. Mechanical failure: The mechanical components of the crane may also malfunction, such as chain wheel deformation or jamming, which can also cause the chain to get stuck.

If the chain of the electric chain hoist is found to be stuck, the following methods can be used to solve it:

1. Refueling: For chain jamming caused by long-term lack of refueling, you can try operating the chain within tens of minutes after refueling. If there is improvement, it indicates that the chain jamming is caused by surface hardening of the chain.

2. Replace the chain: If the jamming problem is severe and cannot be solved after refueling, the chain needs to be replaced. When replacing, it is important to choose a chain that matches the electric crane and avoid using chains that are too large or too small.

3. Cleaning the chain: Before replacing the chain, you can try cleaning the chain first. When cleaning, appropriate cleaning agents such as gasoline or kerosene should be used. Use a brush to wipe the chain and dry it with a dry cloth or hair dryer.

In short, the problem of chain jamming in electric cranes needs to be resolved in a timely manner to avoid any impact on work. Refueling, replacing the chain, or cleaning the chain are all effective methods to solve the problem.