The efficient cooling of submersible motors is a topic of ongoing discussion among well operators. One less-than-ideal solution is derating, which can result in energy and capital costs and larger well diameters. Oil cooling must be carefully considered because if done incorrectly, it can cause severe ecological damage. The following sections will outline some basic considerations for cooling your submersible motor. They are based on years of experience from other well operators.
high voltage motor
A submersible motor works underground. Therefore, it is important to choose the right cabling when choosing the submersible motor. A long cable has many important characteristics, including leakage inductance, coupling capacitance, and distribution characteristics. Furthermore, a PWM inverter's output pulses will cause voltage reflection and raise the terminal voltage of the motor. This high voltage can damage cables and shorten the service life of the motor. To overcome this problem, a new cable should be used.
Before purchasing a high-voltage motor, you should determine the voltage and phase needed for the system. You should also consider the load for the motor. For example, a 40-hp motor with a 15-percent service factor will meet the load of the system. If you want to purchase a submersible motor that is capable of running in water at up to 500-volts, you should select a motor with a higher voltage.
When selecting a high-voltage submersible motor, check the specification of the power source. You should ensure that the sizing system is correct. Select a motor that has a Class 10 overload protection. Class 10 protection is crucial to the protection of the motor windings. A 460-volt motor can be operated on either a two-phase or three-phase source. The manufacturer will provide you with the exact voltage needed for your project.
medium voltage motor
To start a pump, it is necessary to understand how a Submersible Medium Voltage motor works. The motor starts when its temperature is lower than the system's supply voltage. Then, it continues at a higher speed. To maintain the same running voltage, the voltage should remain at or above its nominal value. When operating on three-phase systems, the starting voltage is typically higher than the running voltage. A compensatory "fudge factor" is used to maintain an adequate running voltage.
In a 480-volt system, a maximum of 5% drop in voltage may be allowed. At that point, the remaining voltage should be at least 456 volts, which is about 2 volts below the motor's nameplate value. Also, the stepped-down voltage of the submersible motor will keep its operating range within acceptable limits, extending its life. Aside from avoiding the above problems, the voltage of a Submersible Medium Voltage motor should be checked regularly.
To determine the safe operating temperature of a Submersible Medium Voltage motor, it is necessary to know its maximum rated current. The motor's nameplate and technical data provide this information. These plates will also contain a "KVA Code" whose letters correspond to the range in KVA/HP. While the mid-range value is a general guide, the exact locked rotor amperage may vary by 2%.
high voltage motor wiring
The correct installation of high voltage motor wiring for submersible motors is critical for proper operation. Submersible motors can be incredibly unforgiving when it comes to proper power supply wiring. The length between the power source and motor can result in a large voltage drop and local condition known as flicker. The correct wiring for submersible motors must be carefully calculated to ensure proper voltage at the motor.
The initial voltage to be used should be at least 10% higher than the nominal voltage of the pump. If this voltage is too low, the pump could fail and the pump would not function properly. The nominal voltage of a three-phase system is usually higher than the motor's nameplate voltage, allowing for a safety factor. Ensure that the cable is long enough to prevent a drop of over 20%.
The lockable rotor amperage is necessary to determine the allowable inrush current. This information is typically included on the motor's technical data or nameplate. A typical midrange value is a reasonable guess. This figure can vary by as much as 2%. Make sure that you understand the corresponding voltage before installing the motor. A high voltage motor should be able to handle the maximum load of the load in its intended location.