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SubMonitor: Protection Flexibility

In our last post, we started a series on SubMonitor. By way of a quick review, SubMonitor is one of the three types of overloads used for 3-phase submersible installations. The three types are heaters, adjustable solid state, and electronic. SubMonitor falls into the last category and although SubMonitor is classified as an electronic overload, it offers far more than simple overload protection. In the next few weeks we’ll take a look at all the capabilities and flexibility SubMonitor offers.

All overloads for Franklin submersible motors must be Class 10 Quick Trip. This means they must take the motor off-line within 10 seconds of the motor reaching five times service factor amps. Overloads must also be ambient compensated, meaning they must trip consistently at the same overload value regardless of the ambient temperature. Ambient compensated overloads must always be used when the motor and the overloads are in different locations and therefore at potentially different temperatures. In the case of a submersible installation, the overloads are in the panel above ground and the motor is obviously submerged underwater. As a result, they will be at different temperatures and hence the need for ambient compensation.

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More than an Overload

In our last post we touched on SubMonitor and its capabilities. Over the next several weeks, we’ll take a closer look at SubMonitor and what a critical role it can play in protecting a 3-phase installation.

Before we get into the details of SubMonitor and all of its capabilities, let’s look at it in the context of overloads in general. Although SubMonitor offers far more protection than just as an overload, it functions primarily as an overload.

Overloads, the Basics:

Overloads play an important role in protecting submersible electric motors from overheating. There are two primary conditions that cause a motor to overheat and fail: a lack of cooling flow past the motor, and high current (amp) condition. While the first condition is straightforward, a high current condition may be caused by several factors including low voltage, high voltage, a ground fault, or an imbalance in a 3-phase system. Regardless of reason, power needs cut when the motor overheats. The type of protection used dictates motor survival; if you’re using the wrong overload, the motor won’t survive.

Overloads for all Franklin Electric submersible motors must be Class 10, Quick Trip, meaning it must take the motor off line within 10 seconds of the motor reaching five times service factor amps. These overloads must also be ambient compensated. That is, they must trip consistently at the same value regardless of the ambient temperature.

Overloads and Franklin Electric:

In the case of Franklin Electric single-phase submersible motors, Franklin Electric always supplies the overload, either in the motor itself or in the control box.

With Franklin Electric 3-phase motors, however, a 3-phase panel is needed with the required overloads inside the panel. These overloads need to be specified and supplied by the installer or electrician.

The most basic type of 3-phase overload is what’s called a heater. These are the oldest and most conventional. As current increases in the overload, the “heater” causes a bimetal contact to bend, thereby opening the circuit.

Moving up in sophistication is generally what’s known as adjustable solid-state overloads, such as the ESP100. A caveat on these products is that they must be set to full load amps, not service factor amps. (These values can be found in the AIM Manual starting on page 22.)

Despite motor type, if you are working with a 3-phase system, all the work of picking the right overload is done for you on page 29 of the AIM Manual. Here, you will find the proper Class 10, Quick Trip overloads, both heater- and adjustable-type.

SubMonitor – More than an Overload:

Now that we have reviewed overloads and their functionality, we can look more deeply into what sets SubMonitor apart from typical overloads.

While SubMonitor is an overload, it’s also more. The SubMonitor offers flexibility unavailable in other protection devices. Using the default settings that are already in the unit, it can be very simple and basic to install and set-up. But, if you need a customized set-up for an installation, SubMonitor offers a great deal of flexibility and even more protection

Join us next week as we start a series on the SubMonitor and all that if offers in system protection.

 

Even More System Protection: SubMonitor

While Pumptec and its extended family are great options for protecting single-phase systems from adverse conditions, what kind of protection is offered for three-phase systems? This week’s Franklin AID will answer that very question.

SubMonitor is designed to protect any three-phase motor rated from 3 to 200 horsepower (5 to 350 amps). SubMonitor protects submersible and aboveground systems from conditions such as low-yielding wells, pump damage, clogging, bound pumps, and power mishaps, which can be the result of overload, underload, high and low voltage, phase loss and reversal, rapid cycling, false start, or overheating. Continue reading

Pumptec’s Extended Family

In our last post we discussed Pumptec and how it protects single-phase submersible systems from damage. The protection doesn’t stop there, however. Franklin offers two other members of the Pumptec family, specifically designed for Franklin single-phase motors.

QD Pumptec is very much like Pumptec in functionality and how it works, but in a smaller, unique package that quickly installs in a QD Control Box. Using power factor to monitor Franklin 230V submersible motors from ½ to 1 horsepower, QD Pumptec protects against the same adverse conditions as the original: overload, underload, high and low voltage, and rapid cycling. This specific product is often thought of as mini Pumptec because it is designed exclusively to fit inside Franklin QD control boxes.

Also offered in the Pumptec family is Pumptec-Plus. Sometimes called the “big brother,” Pumptec-Plus protects against those same five conditions, but it works with any 230 V single-phase motor ranging from ½ to 5 horsepower. Unlike its Pumptec companions, however, Pumptec-Plus monitors wattage rather than power factor. When watts run 25% higher or lower than operating load, Pumptec-Plus will remove power from the system. We can get a good idea of what our operating watts should be by turning to page 13 of our AIM Manual. Let’s say we are working with a ½ hp, 4-inch, three-wire motor. That motor should operate between a full load of 670 watts and a maximum load of 960 watts.

Since actual running wattage varies by motor, each Pumptec-Plus needs to be calibrated at installation. This calibration allows the Pumptec-Plus to tailor its performance to each specific system so that it can be used with any ½ to 5 hp, single-phase, 230 V motor—even those not manufactured by Franklin.

The system lights on the face of Pumptec-Plus are also an important feature; their color and state (steady vs. blinking) tell you exactly what’s going on with the system. Some installers actually keep a Pumptec-Plus with them as a diagnostic tool. If a problem turns out to be intermittent, they can install the Pumptec Plus and have the homeowner make note of what the lights are doing when the problem occurs.

No matter what type of system you are installing, it’s important to protect your investment. Taking the time to look into protection options can save time and money for you, as well as your customer, in the long run. For more information about how to protect your investment in the field or for troubleshooting help, contact our Technical Service Hotline at 800.348.2420 or hotline@fele.com.

Protect Your System 5 Ways

Last week, we reviewed “drought insurance” for submersible water systems using the Pumptec family of products. This week, we will look specifically at Pumptec and how it protects a system from damage in many other ways.

Pumptec is a microcomputer-based pump protection device that monitors load and supply voltage in single-phase systems. It protects against five conditions that can be dangerous to a motor: underload, overload, high voltage, low voltage, and rapid cycling.

Underload, also known as dry well, includes any condition that leads to the motor becoming “unloaded”. Besides a dry well, this could be an air- or gas-locked pump, failed impellers, a line blockage, or a check valve that is stuck closed. Any of these will cause the motor to unload. Once the unloading reaches a predetermined threshold, Pumptec will remove power from the motor.  Anytime an underload condition occurs, the load light will come on steady and stay on until the reset time is achieved. This reset time can be set from two minutes to four hours, or a manual reset can also be specified.

Overload is the very opposite of underload and can occur when the pump becomes clogged with sand or other debris. If this happens, Pumptec will cut power to the motor and the LOAD light will flash. Unlike an underload, there’s no reset time for an overload condition. Pumptec assumes that it warrants investigation and probably won’t restart. The unit must be manually reset by cycling power to the unit.

In both of these situations the system goes from pumping a normal amount of water to pumping very little or no water. To monitor these conditions, Pumptec uses a threshold point on the power factor curve. As we know from our previous AID, power factor is the relationship between voltage and current. Each motor rating has a unique power factor curve, and thus a unique trip point.

If a motor experiences a loss of water for any reason, the power factor of the motor begins to drop rapidly. When it gets too low (i.e. reaches the threshold), Pumptec shuts off the motor and allows the well to recover. After a predetermined timeout, the system will come back on; however, if the load does not reach or exceed the needed power factor, the system will shut off again. If power factor gets too high, Pumptec will also shut off the motor, but in this case, a manual restart is required. You can see how these power factor scenarios correlate to underload and overload conditions.

As we mentioned earlier, Pumptec not only protects against underload and overload but several other damaging conditions.

High or low voltage can create a multitude of problems for a motor electrically. That’s where Pumptec comes in: to monitor the installation’s supply voltage. If voltage drops below or exceeds 10% of the rated voltage (either 115 or 230 volts), Pumptec will automatically shut down the system.  If the voltage is low, the voltage light will come on and remain steady; if the voltage is high the light will flash.

Rapid cycling is the final condition monitored by Pumptec. Characterized by too many starts in a given period of time, it is most often caused by a failed pressure tank or switch. Because rapid cycling can cause serious damage to an entire system, when it is detected, Pumptec will remove power from the motor until it is manually reset.

It is important to note that because Pumptec monitors power factor, which is a unique measurement for each motor design and rating, this protective device cannot work on just any motor. Pumptec is uniquely engineered and designed to work only with Franklin Electric submersible motors from 1/3 through 1.5 horsepower.

For more information about Pumptec please visit our website and be sure to stay tuned for next week when we will continue to explore the Pumptec family of products.

Drought Insurance

Even with reliable brands and installation, some conditions are simply out of our control. For instance, half of the U.S. is currently experiencing a drought and has been for some time. During drought conditions, water levels in a well may drop below pump intake, causing an underload situation. With the lack of snow during the past winter and little rain during the spring and summer, wells could experience this drop either temporarily or long term.

Without significant rainfall to recharge aquifers, many private well systems are susceptible to the adverse impact of dry well conditions. If a well goes dry, the underload condition it causes can destroy the pump and/or motor.

Monitoring and diagnosing load issues can save a pump from damage and potential system failure caused by drought. Investing in a protection device before trouble hits can save a lot of time and money for you and your customer in the long run by shutting down the system to prevent damage when a dry well occurs.

Pumptec, for example monitors motor load and power line conditions to provide protection specifically against dry well/underload, as well as for waterlogged tanks and abnormal voltage. Upon detecting a fault, it interrupts power to the motor to give the well a chance to recover.

Franklin Electric wants to help make guarding systems from dry well conditions as easy as possible and Pumptec products are an ideal way to ensure a long and reliable pump life. During a lack of precipitation like we are currently experiencing, wells are more prone to going dry, due to either a drop in the water table or the fact that the well is getting used more. Sometimes the best investment isn’t the product itself, but what you do to protect it. We encourage you to protect your investment and make sure that once you put a pump downhole, you won’t have to see it again.

For more information about Pumptec, please visit our website, or get more information on how to protect a submersible water system from adversity, contact our Hotline at 800.348.2420 or hotline@fele.com.

 

Column-by-Column: Locked Rotor Amps and KVA

In our column-by-column review of single-phase motor specifications, we are finally at the last two columns on page 13 of the Franklin Electric AIM Manual. These two columns are Locked Rotor Amps and KVA Code.

Locked Rotor Amps, sometimes abbreviated LRA, is exactly what the name implies. If the rotor is locked and can’t move while electrical power is applied, the motor will draw this many amps. Locked Rotor Amps are much higher than running amps, generally around five times max running amps. For example, maximum load for a 1.5 hp, 2-wire motor are 13.1 amps. Locked Rotor Amps for this same motor are 66.2 amps.

An example of when the motor draws Locked Rotor Amps is in the case of a bound pump. In this scenario, the motor’s overloads will trip and take the motor offline in a few seconds to protect the motor.

However, another, much more common instance where the motor draws Locked Rotor Amps is at start up. That is, every time a motor is started, it pulls Locked Rotor Amps for a split second. The reason is that at the moment electrical power is applied, the rotor hasn’t started to rotate yet. So, for that instant, the motor thinks the rotor is locked. Once the motor starts to turn, amperage falls to something between full load and maximum amps. Once again, this happens very quickly, in a few tenths of a second.

Knowing the value of Locked Rotor Amps can be important in some installations, especially in terms making sure we’ve got the appropriate electrical service. For example, many older homes still have 50 amp service. So a 4-inch, 2-wire, 115 volt, ½ hp motor that pulls 64.4 amps at start up could potentially fail to start. There simply isn’t enough electrical current available to get the motor started. The equivalent 230 V motor in this case would be a much better option.

Locked Rotor Amps is also an important aspect of sizing reduced voltage starters (RVS). Reduced voltage starting is one type of soft starting, and these devices “ramp up” the voltage versus applying the full voltage all at once. This greatly reduces the Locked Rotor Amps at start-up.

Reduced voltage starters are rarely used with the single-phase motors listed here. However, if they were, this is where KVA Code comes in, and is used to specify the size of reduced voltage starters. Since reduced voltage starters are much more common and important with higher horsepower, 3-phase motors, we’ll save explaining where the KVA Code comes from when we discuss 3-phase motor specifications.

That wraps up the eighteen columns on page 13 of the AIM Manual. Next week, we’ll jump over to page 14 and start covering fuse and circuit breaker sizing.

For more help in the field concerning troubleshooting and installation, call our Technical Service Hotline at 800.348.2420 or email at hotline@fele.com.