Problem with Crane Starter

A 7.5hp motor? 60-70a sounds more like 75hp.

Are there any places in the drive line you can change the drive ratio(s), lowering the speed that the crane picks up will give you better start up conditions.

Having too much cable on the drum, will also have a negative effect on start up, does the crane work better w/all the cable out?

Is this a recent occurence? Have you checked bearings? Is the brake coming off? Some `Demag` cranes I worked on had a brake that was activated by the supply coming on to the motor, i,e, the brake came off first before the motor turned,

Did you try a severe duty soft starter?

I will increase the hp and the amps of the soft starter.

Did you measured the Power Factor during the starting of the crane? May be you have to compensate the reactive power.

While You seem to have something that is putting an excessive load on the motor 60amps would not be out of the normal for what you're describing. And while I agree with Garthh that to much cable is likely you really do need to thoroughly go through the motor and be sure the bearings and windings are in good shape.

However all that aside the problem you are describing is commonly called a startup inrush and the simple solution to the problem is to install a Capacitor in line. Any basic electrician or Maintenance Engineer should be able to install this in thirty minutes or so.

If you already have a capacitor then you need to get it checked and/or replaced. If it is good then you need to make sure it is wired in properly and if it is you then need to completely go through the motor.

I noticed you gave a good amount of information in your description but to solve this problem you really need to know the amp draw under normal operation. Knowing this will tell you if your problem is the motor it's self or an outside source putting too much load on the motor at start up.

I think its normal, neednt fuss on it. generally speaking, there is a 3--5times over current for motor to start load. Your motor is 7hp, at 38ovoltage, it will be 14A current. multiply 5 is just 70A. after it goes into stable, the current will reduce to 10 about amp.
If you want to reduce the instantaneous current, you can use a soft starter or add a spring at teh end of the wire.
you can also use an invertor for reducing further more.