Slide 3

The ESP's motor is a very specialized piece of equipment that has taken years of development. The motor which is very small in diameter, is able to produce an enormous amount of power, which is translated to the fluid.

The pump is connected by a very large electric cable to a surface unit. From this surface unit, the operator can control the power input, which controls the fluid flow rate. The motor turns roughly at 3,500 rpm which is about 60-Hz power. Most units can operate between 230 and 5000 volts depending on fluid needed.

How is it constructed?
"A wound stator comprises an unwound stator, electrical windings, and insulation and encapsulation systems. The unwound stator has thousands of electrical-grade steel laminations stacked in the housing and is compressed to hold them aligned and stationary. The laminations are die-punched with a center bore for the rotating components to fit into and 18 winding slots for the winding wire. Each slot is insulated with a very-high-dielectric-strength polyamide insulation material. This slot insulation provides winding-to-stator (turn-to-ground) electrical protection.

Insulated copper wire called "magnet" wire or "mag" wire is then wound into each slot to form three separate phase coils displaced at 120° intervals. The insulation on the mag wire provides wire-to-wire (turn-to-turn) electrical protection. Also, at the end of the lamination stack, where the coil has to make a 180° winding turn ("end turn"), insulation is placed between the first winding phase and the motor housing and then between each phase. This protects for phase-to-phase faults.

After the mag-wire winding and insulation is complete, the wound stator is then encapsulated with either a solid-fill epoxy or varnish coating. The encapsulation process fills the voids left in the slots and around the end-turn coils. This provides several important functions. First, it mechanically holds the windings to resist movement that causes wire-to-wire rubbing and possible damage to the wire’s insulation. Second, it adds dielectric strength to the slot winding and end turns. Third, it significantly improves the overall thermal conductivity for better heat dissipation from the motor core through the slots to the motor housing skin. And last, it protects the winding from an attack by contaminates such as wellbore fluid. The last two are less significant for the varnish coating method. As its name implies, it is just a thin coating, mainly on the surfaces of the lamination slots and the mag wire, and has voids where motor lubricating oil accumulates, reducing both the thermal conductivity and the dielectric strength. (ESP Motors)"

                                                                                C    =    constant = 3,960, where Q is in gal/min, and TDH is in ft [= 6,750, where Q is in m3/D, and TDH is in m]
                                                                                N    =    rotating speed, rev/min
                                                                                T    =    torque, ft-lbf
                                                                                Q    =    flow rate, B/D [m3/d]
                                                                                ηp    =    pump efficiency

http://petrowiki.org/ESP_motors

Heat from the motor:
Since the motor is operating at extremely high rpm's and almost non stop, it generates a lot of heat. Due to the motor being mounted underneath the pump, formation fluids are able to come into contact with the outer casing of the motor. The heat is then transferred into the fluid. This is good in two ways. It not only cools the motor, but it heats up the fluid which makes it more viscous and easier to pump, as well as handle on the surface.

How Does It Work?

The Motor