Why you may not be getting the optimum from your wetblast unit
The direction of rotation of a 3–phase motor can be changed by reversing two of its stator leads. This interchange reverses the direction of the rotating magnetic field within the motor. Like many industrial workshop machines, the Dana-Ridge wetblast units are polarity sensitive, meaning they are designed to work with the motor running in one direction only. Unlike some other machinery in your workshop, it can be hard to recognize the issue with a wetblast pump as they will still technically work in reverse, albeit at a reduced capacity.
We know of several cases where our wetblasters have been used in reverse for many years with customers remaining impressed with the abilities of the machine. Upon rectifying the polarity issue, they are then stunned by how much better it becomes.
Single phase (240V) units are turning the correct way when they leave our workshop but 3 phase units are usually hardwired onsite by the customer. Even if it is done correctly upon installation, there is no guarantee it will stay running in the same direction forever. We have seen larger businesses where on-site electrical work has been performed and the polarity at the main board has been inadvertently swapped and affected all machinery plant-wide. Because the wetblaster ‘keeps on trucking’ it can be missed that some processing time and efficiencies have been lost.
With an assistant to start and stop the slurry pump, you can check the direction of rotation by looking at the motor from above and ensuring the motor fan is spinning in a clockwise direction as per the illustration above.
The diagram above shows the bottom casing of the pump and as the pump moves the slurry around, it sends it to the process gun where compressed air is then applied. If the direction were reversed then the slurry will be delivered at a much-reduced rate as it fights against the natural path inherent in the design.
