Q. When installing submersible vertical turbine pumps, what driver characteristics must be considered?
A. While it is important to comply with the manufacturer’s installation instructions for all equipment, this is imperative for submersible pumps to avoid start-up failure, since the unit cannot be observed at this stage. Submersible motors vary greatly in basic construction, so only a few general guidelines can be provided.
For storage prior to installation, the manufacturer will specify whether the motor should be kept in a horizontal or vertical position.
For motors filled with either oil or other special fluid, check for leakage at the shaft seal prior to installation. Check the fluid level in the motor and refill with the manufacturer’s recommended fluid per the instructions, if required.
If the power cable is to be connected to the motor terminal box in the field, make sure the connection is dry and the gaskets undamaged before bolting up the joint.
Keep the reel with the power cable close to the wellhead so that the cable insulation does not become damaged by being dragged over the ground or over the well casing flange when the unit is lowered into the well. Similarly, clamps for securing the cable to the discharge pipe should not have sharp edges.
The couplings for the discharge pipe joints should be securely tightened to prevent the motor’s induced starting torque from either loosening or further tightening the joints. This would cause the power cable to spiral around the pipe and could cause cable or terminal failure. When the unit has been completely installed, a meg-ohm reading should be taken on the cable/motor per the manufacturer’s instructions to verify complete electrical integrity. If the meg-ohm reading is below the manufacturer’s recommended minimum, the problem should be identified and corrected before the unit is started.
Electrical splices and connections must be waterproof. Make a strong mechanical bond between the motor leads and the cable to avoid high electrical resistance at the connection. A poor mechanical connection or a poorly wrapped splice can cause motor problems and motor failure.
The necessary electrical controls should be provided in the starting panel. Most manufacturers recommend a time-delay relay to provide for time delay between stops and starts.
The Hydraulic Institute has recently made extensive revisions to its Standards for Rotodynamic (Vertical) Pumps, including ANSI/HI 2.1-2.2 for Nomenclature and Definitions, ANSI/HI 2.3 for Design and Applications and ANSI/HI 2.4 for Installation, Operation and Maintenance. These standards contain additional details related to the above topics and serve as must-have references for anyone working with Vertical Turbine Pumps.