I recently received a phone call from an electrician at a quarry that was experiencing a high amp draw on a newly mounted electric vibrator that replaced a competitor’s vibrator. The nameplate on the vibrator indicated the Full Load Amps (FLA) at 1.4 amps, but he was getting readings above the nameplate rating. Fortunately, he shut the motor down and contacted us.
I normally ask these questions to help troubleshoot an issue like this:
- What is the application?
- What are the dimensions of the hopper or bin?
- Is there material in the hopper or bin?
- How is the vibrator mounted to the vessel?
Application Details
After getting information for this particular application, I determined that the vibrator was properly sized given the vessel dimensions and the material characteristics. The hopper was full of material so the vibrator was not being operated on an empty vessel - which is strongly advised against! And the vibrator was properly mounted to a sufficiently sized C-channel and mount plate.
After further discussion, I asked for a visual inspection of the channel to make sure it is welded properly to prevent any flexing. The welding on one side of the channel had actually broken, causing the vibrator and channel to flex. When an electric vibrator is not rigidly mounted, the resulting flexing causes the motor to “fight itself," creating the amp draw to increase.
Simple Fix
The customer repaired the channel mount with a specified stitch welding procedure. The vibrator then ran successfully and helped properly discharge material, all while running below the nameplate amp rating.
All too often, I find that customers “burn up” electric vibrators due to improper mounting as well as improper overload protection.
Proper Mounting
To ensure a rigid mount, an electric vibrator should be mounted on a channel or beam of sufficient length, width, and weight as specified in the operator’s manual.
Improper Overload Protection
If a vibrator motor is not protected from overload, the vibrator can be destroyed which is not covered by warranty. Overload, short-circuit, and ground fault protection should be determined according to the NEC Article 430.
In closing, if you are ever struggling with a vibrator's desired result, don't hesitate to reach out. It could be a simple fix where we can save you a lot of time and stress.
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