Franklin Pump — Franklin Electric Submersible & Borehole Pumps
Franklin Electric submersible motors and borehole pumps for deep wells, municipal supply and irrigation in Thailand — how the motor and pump end work together, and how to specify the right one.
What Franklin Electric builds
Franklin Electric is best known for submersible motors — the sealed motor that sits below the water in a borehole and drives the pump above it. The motor and the pump end are separate engineering problems, and understanding that split is the key to specifying a Franklin pump correctly.
The motor is water-filled and relies on the surrounding water for cooling. Its stator is hermetically sealed so that the winding is isolated from the well water, and its bearings are water lubricated. That construction is what allows the unit to run continuously, submerged, for years at a time.
The motor and the pump end are chosen separately
The pump end determines how much water and how high. The motor determines whether that duty can be sustained without overheating. Getting one right and the other wrong is the usual cause of premature failure.
- Pump end — number and shape of stages set the flow and head. Materials are chosen for the abrasiveness of the water, particularly where sand is present.
- Motor — sized to the shaft power the pump end demands at the actual duty point, not at the pump's maximum rating.
- Cooling flow — the motor needs water moving past it at a minimum velocity. In a wide borehole or an open tank, a flow sleeve is often required. This is routinely overlooked and routinely fatal to the motor.
Getting the sizing right
Two numbers decide everything, and neither of them is horsepower:
- Flow required, in cubic metres per hour at the point of use — derived from what the system actually consumes, not from the largest figure on a datasheet.
- Total head — the vertical lift from the lowest seasonal water level to the discharge point, plus friction losses in the pipework, plus any pressure the outlet requires. Long pipe runs frequently contribute more than the vertical lift does.
Take those two figures to a pump curve and select the model whose duty point sits close to its best efficiency region. Oversizing does not produce better water; it produces higher energy consumption every month and operation away from the point the pump was designed for.
There is also a well-side limit that is easy to miss: if the pump draws water faster than the borehole yields it, the water level falls to the pump and the motor runs dry. Well yield must be established before pump selection, not after.
Why 50 Hz matters in Thailand
Thailand runs on a 50 Hz supply. An induction motor turns at a speed set by the frequency it is fed, so a unit built for a 60 Hz market runs roughly one sixth slower here. Flow and head both drop accordingly, and the published performance curve no longer describes what you will get.
The failure mode is quiet: the pump still runs and still delivers water, so nothing looks wrong until the system underperforms against its design. Always confirm frequency, voltage and phase on the actual nameplate before ordering.
Where Franklin pumps are used
- Deep borehole water supply for plants, estates and municipal waterworks
- Village and community water supply schemes
- Agricultural irrigation, including systems driven by solar arrays
- Long-distance transfer where head, not volume, is the governing constraint
What to confirm before ordering
- Required flow and total head at the real duty point, not peak catalogue values
- Borehole diameter, depth, and the lowest seasonal water level
- Tested well yield, so the pump cannot outrun the source
- Electrical supply at site — frequency, voltage and phase
- Whether a flow sleeve is needed to guarantee motor cooling
- Motor protection against dry running, over-current and over-temperature
- Spare parts availability in Thailand and realistic lead time
Frequently asked questions
How do I know what size Franklin pump I need?
Establish the flow you need per hour and the total head the system must overcome, including friction in the pipework. Those two figures locate a duty point on the pump curve. Horsepower is the result of that selection, not the starting point for it.
Why did my submersible motor fail so quickly?
The most frequent causes are dry running when the water level dropped, insufficient cooling flow past the motor, and electrical supply that did not match the nameplate. All three are preventable at specification and installation stage.
Can a 60 Hz pump be used on Thai 50 Hz power?
It will physically rotate, but roughly a sixth slower, so flow and head fall short of the published curve and the system will not meet its design. Where the reverse is attempted — a 50 Hz unit on 60 Hz — the motor draws more current and runs hotter than intended. Match the nameplate to the supply.
What is a flow sleeve and do I need one?
A flow sleeve forces water to pass along the motor body at sufficient velocity to carry heat away. It is typically required when the pump sits in a borehole much wider than the unit, in an open sump or tank, or where the inflow enters below the motor. If in doubt, have it assessed rather than assumed.
Are Franklin pumps suitable for solar-powered irrigation?
Yes, and the combination is common in Thai agriculture because pumping demand coincides with daylight. The system design differs from a mains-fed installation, particularly in how the drive handles variable input, so specify the intended power source from the outset.
How do I confirm I am buying genuine product with local support?
Ask who carries the warranty in Thailand, request the nameplate photograph before purchase, and confirm whether the seal kit and impeller for that model are stocked locally. Those three answers separate a supported supply from a parallel import.
Related pages
Need help sizing a water system?
Talk to our engineers for a preliminary assessment.