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Frequently Asked Questions (FAQ's)

We have collected some of the most frequently asked questions and requests for information from customers and consultants.  For easy reference, the information is organized by general product category.  If your immediate question or information need is not addressed here, you are invited to contact your local sales representative or SEECO and we will gladly assist you with your information request.  We would also welcome your recommendations for additions to the FAQ list.


General Questions About SEECO

Phase-Over-Phase GOABS(R)

Motor Operators

Current and Voltage Sensors

Vacuum Interrupters - Multi Bottle

Vacuum Interrupters - Single Bottle

Other Interesting Questions We Are Still Pondering

General Questions About SEECO

1.  How did SEECO get started?

SEECO was founded in 1920 when several engineers that worked for Duke Power Company left to start their own business.  For the complete SEECO story, please refer to the Our History web page.

2.  How large is SEECO?

SEECO is a privately held corporation and does not release sales or financial information.  What we can share is that SEECO now has two manufacturing facilities and employs approximately 70 people.  Our company growth over the past 10 years has been explosive,  making us one of the fastest growing suppliers to the electrical utility industry.

3.  I thought you only made phase-over-phase switches. 

While we are nationally recognized for our phase-over-phase switches, SEECO manufactures several other commercially successful products, including motor operators, vacuum interrupters and line post sensors.  The reputation of these products is growing and gaining national recognition in their own right.

4.  What is your typical lead-time? 

Standard lead-times for all manufactured products average 6-8 weeks (ADA), with drawings 3-4 weeks (ARO).  Lead-times can vary due to order activity, product mix and time of year.  If more urgent delivery is required, please contact SEECO for assistance.  We can often do better than our quoted standard lead-times.

5.  What is your lead-time on spare parts?

Most spare parts are shipped within 24 hours of the receipt of your purchase order.  Orders received before 12:00 noon EST may be shipped the same day.


Phase-Over-Phase GOABS(R)

1.  What is toggle?

Toggle is the positioning of the rotating insulator reach rod, crank arm and clevis assembly into a bind at the end of the closing operation.  The benefit of toggle is that it prevents the accidental or unintended opening of the switch due to conditions such as excessive pole deflection or vibration, galloping conductors, insulator deflection and torque or distortion of the switch support structure.  Toggle is a simple mechanical convention to insure reliability without the use of blade locks or other latching devices.

Toggle is required for proper operation of all SEECO switches.  Field installation and switch adjustment are not complete until the switch has been adjusted for toggle.  A more complete description of the toggle adjustment procedure can be found on pages 14-15 of our installation instructions for phase-over-phase switches.

2.  What is the recommended maintenance for SEECO switches?

Our recommended maintenance is minimal.  We recommend that all switches be operated at least once each year to insure the freedom of movement of mechanical components and linkages.  If this frequency cannot be met, then operate the switch as often as conditions permit.  Visually inspect all moving components for significant wear or signs of damage.  Male and female contacts should be wire brushed lightly to restore a clean contact surface area.  We do not recommend the use of contact grease.  Observe switch operation and compare the engagement of live parts, interrupting devices and over toggle components to the recommended operation as described in the installation instructions.  Operation of the switch should be smooth, with minimal operating effort to open or close the switch.  No slamming is ever required.

If you have questions after visual inspection and operation, please do not hesitate to contact SEECO for additional information or assistance.

3.  Will SEECO coordinate the switch mounting details with the pole supplier?

Yes.  It is a standard procedure for our application engineers to coordinate the details of switch mounting with the suppliers of engineered pole structures (steel, concrete, laminated wood).  We forward framing details to the pole supplier and we review the pole structure drawings submitted to us by the supplier to confirm correct hole patterns, including number, location and sizes. 

Note: We do not review the design specifications for the pole.  This is the responsibility of the customer or the customer's consultant.

4.  Can phase-over-phase switches be mounted on wood poles? 

Yes.  The unique design of SEECO's phase-over-phase GOABS withstands changes to wood pole structures more readily than other brands of phase-over-phase switches, especially those utilizing blade latching type devices.  The "tulip" design of our female jaw contacts is very forgiving and allows for a significant amount of switch insulator displacement without loss of contact pressure between male and female contacts.  The toggle adjustment insures that the rotating insulator stays locked in the completely closed position, irrespective of the degree of pole structure and switch frame deflection or switch insulator displacement.

All SEECO phase-over-phase switches rated 69 kV and below can be mounted on wood pole structures.  One-way switches rated 115 kV and up can also be mounted on wood pole structures.  We strongly recommend that two and three-way switches rated 115 kV and up be mounted on engineered structures (steel, concrete, laminated wood), designed for the specific loads and line tensions of the application.

5.  Can I dead-end tap and through line conductors directly to the switch support structure?  Won't this cause future maintenance and adjustment problems?

For general guidance, you should have no hesitation to dead-end conductors and strain insulator assemblies directly to the switch frames, unless you have very severe angular pull-offs or unbalanced line tensions.  As long as through line tensions are equal and balanced, the aluminum or steel pull-offs provide an economical and convenient means for locating strain insulator assemblies.  Dead-ending conductors directly to the switch frames also serves to stabilize the support structures.

Unlike other switch designs, which employ blade locks and latching devices, SEECO's over-toggle adjustment and unique live parts design will readily accommodate the inevitable twist and deflection of the switch support structure and insulators that occur with galloping conductors and pole deflection.  And for most ratings and configurations, SEECO's aluminum frame structures are designed and fabricated utilizing larger members and thicker material  cross sections than the support structures of our competitors, providing a more rigid and stable platform. 

For questions about angular pull-offs and unbalanced line tensions, or other application specific questions, please contact the factory. 

6.  What are the ratings or limitations for line tensions?

For general guidance, pull-offs are rated for 10,000 lbs line tension (working) on a straight line pull, which is 180 degrees on the thru lines and 90 degrees on the tap.  When angular pull-offs are anticipated, the 10,000 lb line tension allowance must be de-rated.  Please contact SEECO for a table of allowable tensions at various angles or for guidance on line tension requirements that exceed 10,000 lbs.  High line tension requirements can be accommodated but must be coordinated with our application engineering personnel.

7.  Do you provide installation assistance?

Yes.  SEECO personnel can provide assistance with assembly, erection and final product adjustment.  Please refer to the Installation Center for additional information on commissioning, training or other field support services.

8.  Can you provide phase-over-phase switches factory pre-assembled?

Yes.  Factory pre-assembled phase-over-phase switches can save significant field installation time and cost.  Factory pre-assembly also insures that critical assembly and adjustment is made by highly knowledgeable and experienced personnel.

9.  Can you provide live parts for a Turner phase-over-phase switch?

Yes.  Live part conversion kits are available for most Turner switch configurations.  SEECO conversion parts replace the existing Turner components and the modified switch can then be adjusted for toggle.  This is a quick and economical way to eliminate Turner blade locks and the adjustment problems attendant with them. 

10.  Can SEECO provide arcing horns for interruption of line charging currents?

Yes.  SEECO has two styles of arcing horns for transmission switching applications.  Our traditional horn, which is standard on all phase-over-phase switches, is a tapered beryllium rod that provides interruption of line charging current comparable to other available arcing horns.  SEECO has also recently developed a spring loaded, high velocity whip (HVW) that provides substantially higher levels of interruption than traditional horns.  Consult the factory for assistance in determining which style of horn will best accommodate your specific application.

10.  Can I close your switch to pick-up load?

Many customers choose to use the switch to pick-up load.  Though this is not an uncommon industry practice, please note that the switch is not rated for load make and there may be some pitting or burning of auxiliary or main switch contacts; the degree of pitting and burning will depend largely on the line amperage and closing speed. 

[It is generally accepted by industry practitioners that the severity of an arc is substantially less in switch closing than in switch opening.  When closing the switch, the distance between energized male and female contacts is reduced at a brisk rate and does not present as favorable an opportunity for an arc to develop as when opening.]

Weighing the operational advantages, disadvantages and safety considerations, each customer must formulate their own policy for picking up load. 

11. Can I close in on a fault?

The answer is essentially the same as the answer to the previous question.  The switch is not rated for fault closing though some customers choose to do so.  Expect pitting or burning of auxiliary and main switch contacts proportional to closing speed and the amount of fault current.  Again, each customer must formulate their own policy.   

12. What happens if I open your (airbreak) switch to drop load?

You will draw an arc, with the length and duration in proportion to the speed of opening, the amperage of the line, and the point in the sine wave where contact separation occurred.  Other factors that will affect the severity of the arc include, ambient temperature, humidity and wind direction and speed.  In severe cases, an elongated or extended arc may pose a safety hazard to utility personnel and equipment.  

If frequent load dropping is anticipated, we recommend the use of SEECO's Monoruptr(r) vacuum interrupter for arc-less switching.


Motor Operators

1.  Can SEECO provide a motor operator for an S&C switch? 

Yes.  We are one of the largest aftermarket suppliers of motor operators for S&C group operated switches.  We have an operator for any style and rating of S&C switch, including configurations with more demanding motor operation requirements, such as circuit switchers. 

2.  Can SEECO provide motor operators for Turner phase-over-phase switches?

Yes.  SEECO is the leading supplier of electro-mechanical (non-hydraulic) motor operators for Turner switches.  Our operators provide variable speed adjustment in both the opening and closing directions, easily field adjusted for normal open and fast slam close. 

3.  What is the average life expectancy of batteries in 24 VDC units?

Battery life will range between 3 and 7 years and is contingent upon factors such as usage, average ambient temperature, charge variables and the depth of discharge throughout the life of the battery.

4.  Do you offer a solar charging option for 24 VDC units?

Yes.  We are offer a complete solar power supply package which typically includes solar modules (panels), mounting brackets, batteries, charge controller and cabling.  SEECO solar power supply packages can be reliably used in virtually any environment because the charge system is sized for the specific geographical location and the current draw of the motor operator and associated equipment (RTU, radio, etc.).  Where 120 VAC is not readily available, solar can be very economical when compared to the cost of a potential transformer or bringing distribution service several miles to your site.

5.  Why don't you provide a crank handle?

The primary reason is operator safety.  Utility field personnel have told us on numerous occasions that they prefer a swing handle for operation of a disconnect switch under live conditions because a faster speed of operation can be achieved.  Depending on the ratio of the motor operator gear box, it will typically take 12-15 revolutions to fully open or close a switch with a crank handle.  A lineman may be exposed to burning contacts for a longer period of time with a crank handle.

In place of a crank handle, SEECO provides both a swing handle and a torque relief knob as standard equipment.  The swing handle is used for manual operation of the disconnect switch when the motor operator is de-coupled.  The torque relief knob can be used for fine adjustment of the limit switch column during initial installation and will also relieve pressure on the coupling mechanism when coupling or de-coupling is required.  The use of both devices can accomplish all of the functions typically accomplished through a crank handle and provides greater operator safety.

A crank handle option can be supplied (at additional cost) when absolutely required by customer specification, however we encourage you to consider the safety benefits to field personnel when weighing the costs and benefits.  Please contact the factory for additional information on the crank handle option. 

6.  Why do you provide only 8 auxiliary switches?

The auxiliary switches provided are all form "c" style, and can be easily changed from NO to NC using shunts.  This is equivalent to 16 of the old style auxiliary switches which were typically provided as 8 NO and 8 NC.  Practically speaking, 8 form "c" contacts will exceed the requirements for most typical applications.  In the highly unusual event that more contacts are required, SCADA and RTU software typically provide additional logical contacts that can piggyback the 8 contacts supplied.

7.  Do I need a separate enclosure for my RTU and radio? 

No.  SEECO's standard motor operator enclosure (with flush mount door) can accommodate many major brands of RTU, radio, cellular modem or other communication device.  These devices are typically door mounted, which provides ample space and access to motor operator interior components and systems when the door is open.  Smaller, more compact devices may be located elsewhere within the interior of the enclosure as space and function requires.  If the size and profile of these devices require additional space, we utilize a 4" bump out door with clear Lexan cover.

The operational and financial benefits of single enclosure applications are significant and include reduced pole clutter, greatly reduced field installation time and cost and a more consistent and standardized installed product.

8.  Should I ground the return in my RTU enclosure?

No.  The return and positive DC voltages are both floating and isolated for lightning protection.

9.  Can you supply an RTU and communication device?

Yes.  SEECO will purchase and factory install your preferred make (brand) and model, often at lower cost than your organization's total cost to purchase and field install.

10.  Will SEECO install and pre-wire my RTU and communication device? 

Yes.  Purchase these devices and have them shipped to SEECO.  We will install and pre-wire them.

11. Can you supply motor operators with a mounting bracket to match existing mounting holes?

Yes.  We will fabricate the mounting bracket to coordinate with any mounting details that you may provide.

12. Can the battery management system be used in other manufacturer's motor operators?

Yes.  The LAB24 battery management system can be easily retrofitted to any other 24 or 12 VDC system that utilizes lead acid batteries, including control cabinets, motor operators, RTU enclosures, etc.  SEECO can readily provide the battery management system along with DC-to-DC converters, heaters or other system components for easy field conversion.


Current and Voltage Sensors

1.  Does the sensor do everything that traditional oil-filled instrument transformers can do?

No.  SEECO SENSE line post sensors were designed for a fewer number of tasks but to do them more cost effectively and efficiently than general purpose oil-filled instrument transformers.  Our sensors were designed foremost for current and voltage monitoring in transmission and distribution switch automation applications, but they also have use in substation applications (sync relay, voltage monitoring, metering).

Other design objectives included ultra-light unit weight, mounting flexibility, safety and the elimination of oil, SF6 or other polluting dielectrics. 

2.  What is the accuracy of your sensor?

Current sensing is accurate to +/- .15%, and exceeds industry standards for revenue metering.  The accuracy of the current output signal is perfectly linear down to 1% of the rated continuous current.  Voltage sensing is accurate to +/- 5% and is used primarily in non-metering applications.

3.  How much does a sensor weigh?

SEECO current and voltage sensors are extremely light weight and typically weigh less than 10% of comparable oil-filled instrument transformers.  This favorable weight differential allows the use of SEECO sensors in transmission applications where pole mounted oil-filled instrument transformers are simply impractical.  In substation applications, SEECO sensors can be mounted to existing equipment and bus support structures, eliminating the need for dedicated pedestal structures and concrete footers.   

4.  Are there limitations on the mounting orientation?

No.  SEECO SENSE line post sensors can be mounted upright, cantilever (horizontal) and under-hung.  This flexibility in mounting orientation provides significant design and cost advantages over oil-filled instrument transformers.   

5.  Isn't your technology more expensive than traditional oil-filled instrument transformers?

Absolutely not.  SEECO sensors are priced comparable to or less than oil-filled instrument transformers.  When design, safety, operation and maintenance advantages are considered, SEECO sensors are far more cost effective to purchase, install and maintain.

6.  Are the sensor outputs analog or digital?

Analog output signals are standard, however, the outputs are first generated by the sensor units as digital outputs.  These digital outputs are transmitted from the sensor units to an output amplifier where digital to analog converters are used to create analog outputs for use by your devices.

Why do we generate the output signals in digital format?  Digital transmission allows the output signals to travel up to 4,000 feet with no signal loss or reduction in accuracy.  The output amplifier can now be located immediately adjacent to the RTU, meter or relay and the sensor unit placed anywhere in the station or on the pole structure as the application requires.

7.  Should the output amplifier be mounted closer to the sensor or the equipment the output signal is being provided to?

The output amplifier should be mounted as close as possible to the customer's equipment to limit the length of analog output cabling and reduce the effects of noise and signal loss.  [See response to question 6 above.]

8.  Does the sensor require an external power source?

Yes.  The output amplifiers require an external power source, which can be 120 VAC or 24, 48 or 125 VDC.  Unlike traditional PT's, our voltage sensors are for monitoring purposes only and cannot be used to run battery chargers, heaters or other devices.

9.  Can I provide my own cabling from the sensor to the output amplifier?

We do not recommend it.  Given the high number of twisted pairs and the difficulty in wiring the end connectors, we strongly recommend that the cables be provided by SEECO and manufactured to length and pre-tested for accuracy.

10.  Do I need to run the sensor cable inside conduit?

No.  The cable can be direct burial, located in cable tray or secured to exposed conduit or structures.  Use conduit or cable tray where available to reduce vandalism or cable damage but it is not required.

11.  How far can I run the sensor cable?

Up to 4,000 feet.  Specify the required cable length at time of order.

12.  Is the sensor compatible with SEL relays?

Our sensors are compatible with most SEL relays utilizing our standard output signals native.  Consult the factory with your application information at time of order entry to discuss any special requirements.    

13.  Can I charge batteries or use the sensor as a power source?

No.  Our sensors were designed specifically for monitoring applications and do not function as a power source like traditional oil filled instrument transformers.  [See response to question 1 above.]


Vacuum Interrupters - Multi Bottle

1.  What is the life expectancy of a vacuum interrupter bottle?

Vacuum bottle life is determined by two primary factors: 1) mechanical limitation of the metallic sealing bellows, which are rated for 10,000 operations, and 2) contact erosion, which occurs as a result of opening under load.  The vacuum bottle contact are rated by their manufacturer for 7,200 operations at 600 amps, 3,600 operations at 1200 amps and 2200 operations at 2000 amps (current interruption). 

Typically, the actual interrupting current is less than the nameplate rating of the associated group operated switch, therefore the life expectancy in operation is generally greater than these published values.  The mechanical operating life expectancy is probably the upper limit of what you can expect.  In either case, you will likely never reach the design limit in actual use. 

2.  How much current will your interrupter handle?

As a general answer, the vacuum bottle is rated for 2000 amps.  Your experience will be dependent, in part, on your specific application, type of system and switching procedures.  Please consult the factory for assistance in estimating your system requirements and selection of the appropriate SEECO interrupter.

3.  Which dielectric does SEECO use?

For multi-bottle interrupters, SEECO uses a silicon oil as our dielectric.  A solid dielectric is used for all SEECO single bottle interrupters.

4.  Why not SF6?

SF6 is an inert gas, which is significantly harder to contain within a column and is more prone to leakage than oil.  Silicon oil is also safer to handle and doesn't pose as many environmental concerns as SF6. 

From a practical standpoint, leakage of SF6 is almost impossible to detect so a compromised interrupter is more likely to be operated.  Your first indication of lost dielectric will usually be a failed interruption.  If silicon oil leaks from the interrupter column, it will leave a very visible dark stain on the exterior of the column, which provides an opportunity for observant field personnel to recognize and question before operation.

An additional safety concern associated with SF6 is the propensity to backfill with moisture when the gas has leaked out.  During interruption, pressure will build and the interrupter device can explode.  SF6 also produces a dangerous byproduct if subjected to internal arcing within the interrupter column that can be harmful to utility personnel if they are exposed.

Overall, we believe that silicon oil is more stable, safer for field and technical personnel who may handle the interrupter units, and more environmentally friendly.

5.  Do you hi-pot every interrupter?

Yes.  Every interrupter is hi-potted after final assembly and before shipment.

6.  Should we hi-pot the interrupter before initial installation?

This is an issue that each utility must decide for themselves based on their own assessment of safety considerations and cost.  Each utility will have their own sensitivity to these issues and weight them according to their own experience.

If you suspect that the interrupter has been damaged, you should investigate further to resolve your concern.  In general, if the interrupter is received by the customer and there are no signs of damage in transit, it may be sufficient to simply use a voltage tester to confirm the integrity of the vacuum bottles within the column.  A simple visual inspection may be enough to provide confidence to personnel that the interrupters have arrived in the same condition as shipped. If you believe there has been damage in transit, the only authoritative and reliable method to determine the condition of the interrupter is through a complete hi-pot test.

7.  How do I tell if the interrupter has a bad bottle?

If you suspect that a vacuum bottle has gone bad, there are two methods to investigate your concern: 1) a voltage tester, and 2) a hi-pot test.

If there are indications of possible bottle failure on the exterior of the interrupter column, such as burning or arc tracks, a complete hi-pot of each vacuum bottle is recommended.  A procedure for hi-potting the interrupter is available to assist you.  Please contact the factory for guidance and assistance if you have questions.

If there are no external indications of bottle failure, it may be sufficient to employ a voltage tester and check each bottle individually.  With the arms pulled fully open past the  interrupter trip point and the vacuum contacts open, each bottle should register no voltage across the contacts.  With the arms re-set and vacuum contacts fully closed, each bottle should register voltage across the contacts.  If you observe that a bottle may not be holding voltage, you should confirm that observation with a more stringent and complete hi-pot test.

The judicious use of a voltage tester can save you time and effort but it is not as authoritative and reliable as a hi-pot test.  You must choose your method based on your own experience, facts and circumstances.  Please contact SEECO if you have questions or need assistance.


Vacuum Interrupters - Single Bottle

1.  What are the capabilities of a single bottle interrupter?

Single bottle interrupters are used as full load break devices for group operated switches rated 34.5 kV and below.  They are used to interrupt parallel or loop splitting for switches rated 46 kV and above, where the recovery voltage does not exceed 35 kV.  The interrupting current is limited to 2000 amps.

2.  Can you provide single bottle interrupters for retro-fit to other brands of switches?

Yes.  SEECO is now developing retro-fit kits for other brands of switches.  Please consult the factory or your local sales representative for availability to accommodate your brand of interest.


Other Interesting Questions We Are Still Pondering

1.  Is your motor operator bullet proof?

2.  Can your batteries be used in my riding lawn mower?

3.  What will happen if my motor operator is submersed in water?

4.  Can you make the switch and pole structure look like a tree?


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