When purchased without a feeder bowl, it is necessary to 'tune' the unit after the feeder bowl has been installed to obtain proper performance.To determine the tuning condition of a feeder bowl, the following steps should be followed:

   

1. Gain access to the springs.
   
2. Check the air gap - it should not be less than .060" for this test.
   
3. Set the controller at '5' dial setting.
   
4. While observing, slightly loosen one of the spring clamp bolts and note the change of vibration:

If the vibration decreases - the unit is under-tuned.Proceed as follows:

An under-tuned unit is evident by a reduction of vibration when a material load is placed in the bowl. The spring system is not stiff enough. The condition can be corrected either by adding springs to the racks or replacing the present ones with thicker springs. A small change to the spring racks will show a significant change in vibration. Any alterations should be made in small increments. When changing or adding springs, ensure that a symmetrical pattern is maintained on the racks at all times. After each alteration, the air gap should be checked and adjusted if required.

If the vibration increases - the unit is over-tuned.Proceed as follows:

If the current exceeds the name-plate rating, the air gap should be checked and adjusted as per air gap instructions. With the air gap properly adjusted and the current within limitations, check the vibration. If the bowl speeds up excessively when bolt is loosened, it is over-tuned. Simply remove springs or replace with thinner ones, being sure to keep a symmetrical pattern on the racks at all times. After each alteration, the air gap should be checked and adjusted if required.