 |
 |
|
|
Click these links to jump down this page for information on the topics listed:
Office FAQ
Look here for answers to your business electronics protection questions.
Select a topic below. Can’t find what you're looking for? Call the PGE power protection experts at 503-736-5750 or 800-270-7016 or e-mail us.
Lighting
Q. Our office has fluorescent lights with electronic ballasts. They appear to be failing too soon. What should I do?
- The average lifespan of an electronic ballast is 50,000 hours. This means you can expect only half of the ballasts to work after this time and some to fail each year. Good brands of electronic ballasts should last for more than five years and be covered by a manufacturer’s warranty.
Electronic ballasts are generally rated to operate within a range of plus or minus 10 percent of the standard voltage. PGE normally maintains your voltage within a range of plus or minus 5 percent, so minor voltage changes should not effect the life of your electronic ballasts.
Equipment failure due to a power surge is a common customer concern. Minor power surges occur frequently and most of them originate inside a building. Surge suppression is the only good defense against equipment failure due to a power surge.
Q. My HID lighting turns off every time the compressor starts. What can PGE do to help me?
- When the voltage drops below the minimum operating voltage for HID lighting, the lamp goes out and must cool down before it can re-start. In some cases, this can take up to several minutes before the lighting turns on again. As the lamp ages, the minimum operating voltage requirements increase and minor voltage dips can cause the lamps to cycle off and on. The average life of the high-pressure sodium lamp used in most HID lighting is 24,000 hours. If the lamp is approaching the end of its life expectancy, the minimum voltage can increase to a level where minor voltage sags may cause the lamp to turn off. Two of the least costly solutions include replacing the lamps or installing a constant voltage transformer to serve your HID lighting load. If you believe your voltage is lower than it should be, call the PGE power protection experts at 503-736-5750 or 800-270-7016.
Power
Q. I have power problems that seem to be related to nearby construction. Who can I call at PGE to verify that this is the source of the problem?
- During construction it is sometimes necessary for PGE to interrupt the power at some locations, which can result in power disturbances. You can verify whether this is the case by calling the PGE power protection experts at 503-736-5750 or 800-270-7016.
Q. Some of my equipment was recently damaged by a power surge. What can PGE do to prevent surge damage?
- Surge suppressors are placed on most of PGE’s equipment to protect our equipment. Our surge suppressors limit the magnitude of some surges, but they are not designed to protect your equipment. Consider installing surge suppression equipment in your office to prevent this in the future.
Q. We experienced a power problem at our office, and an elevator motor failed as a result. PGE said the problem took place because our location was “single phased.” What can PGE do to prevent this type of damage?
- “Single phased” means one phase of your three-phase service was not available. This can occur if our protection system opens only one phase, and you still have power available on the other two phases. Should this occur, the other phase of a three-phase motor will draw too much current. If the motor’s overload protection does not open quickly enough, the motor will be damaged. Single phasing is a rare occurrence, and protection from this type of disturbance is not included with the standard motor control system. The best solution to avoid this type of problem is to install a “single phasing” sensing relay. A good single-phasing sensing relay should be calibrated for the location where it will be used. Improper calibration of the relay can result in nuisance tripping problems.
Q. My electrician told me our voltage is too low. Who should I call to get this repaired?
- PGE attempts to maintain your voltage within 5 percent of the standard voltage. This means that the voltage may range between 114 and 126 volts for locations with 120/208 volt, three-phase service. If you believe the voltage at your location is below this range, you should contact the PGE power protection experts at 503-736-5750 or 800-270-7016 to verify your voltage.
Q. Our recently installed computer network doesn’t work reliably. We suspect this is related to our electrical system. What can PGE do to help us?
- Many office buildings are not wired to support today’s computer loads. Even new buildings wired according to the NEC may not adequately support sensitive loads like a computer. Networked computers are likely to operate unreliably without the installation of enhanced wiring and grounding. You should contact a network consultant or call one of our qualified PGE-certified electrical contractors.
Q. We have a computer-operated machine that keeps locking up. The technician that worked on it said it was due to power disturbances and suggested we call PGE. Could PGE help determine what is wrong with our power?
- When equipment does not operate correctly and the lockups do not correlate to a disturbance on PGE’s system, the problem is very likely due to an internal wiring and grounding issue. You’ll need to have a qualified electrical contractor track down the problem. PGE maintains a list of contractors who have the experience and equipment to help you. Contact the PGE power protection experts at 503-736-5750 or 800-270-7016 or e-mail us for a referral.
Q. Several times this year our lights blinked. Even these minor disturbances cause my equipment to restart. Can PGE improve my service so this doesn’t happen?
- PGE strives to provide you with safe, reliable service day in and day out but it is not possible to prevent all disturbances. Consider purchasing UPS devices or surge suppression equipment for extra protection. It’s smart to perform a financial risk assessment to determine if potential losses justify the cost.
Devices
Q. I recently bought an uninterruptible power supply device. Now it beeps frequently during the day. What should I do?
- There are many reasons that can cause a UPS to beep, but most are the result of equipment cycling on and off. The most common sources of disturbance that can affect a UPS include a laser printer and/or photocopy machine connected to the same branch circuit, or a large motor load, such as the heating/ventilating/air conditioning system or air compressor, serviced from the same electrical panel as the UPS.
The best solution for this type of problem is to move the UPS devices to another circuit. If you cannot serve the large motor loads from a different electrical panel, you may be able to change the sensitivity of the UPS and still protect your equipment from power disturbances.
If your UPS beeps only once or twice a week, it may mean that the UPS is detecting a minor disturbance within your facility or on PGE’s system. In either case, the UPS is protecting your load from the disturbance and it’s not affected.
Q. There are several different types of UPS devices available. I would like to get one, but do not want to pay more than necessary. What type and size of UPS should I buy?
- There are three main types of “plug and play” UPS devices. The device that works best for you depends on the type of loads and the length of time you want to support them. Read about how to choose a UPS device that is right for you.
Q. I want to protect my office from possible surge damage. What should I install?
- All customers can benefit from the installation of surge suppression at the main electrical service. A high quality unit should handle almost anything coming through PGE’s distribution system, even a direct lightning strike. Additional stages of protection are also recommended at electrical panels servicing critical loads. The price of surge suppression can vary widely depending on the brand and model. In general, the higher the cost of surge suppression, the higher the protection. It pays to consult an electrical contractor or call the PGE power protection experts at 503-736-5750 or 800-270-7016 or e-mail us.
Q. My computer monitor screen wiggles. Is there something PGE can do to fix this problem?
- The most likely reason a screen wiggles is exposure to a magnetic field, known as electromagnetic interference. Often the source of the problem is close by. Is your monitor near an electrical panel or a transformer, possibly on the other side of the wall? Generally, moving your monitor away from the suspected source of the magnetic field can solve the problem.
Electromagnetic interference may also be a result of wiring errors in your building. An engineering company specializing in EMI issues may be needed to identify and solve this type of problem.
If this problem began recently and you are located close to high voltage overhead lines, it may be related to work on PGE's system. Call the PGE power protection experts at 503-736-5750 or 800-270-7016 to report this situation.
Office Tips
Read about common solutions for protecting your office.
You don’t need to be an electrician to understand the basics about electrical power in your office. Four out of five electrical problems result from wiring or grounding issues, while the remainder are related to something happening outside, such as a lightning storm or a car hitting a power pole.
Avoiding power problems
To reduce potentially damaging spikes or power surges at the office, keep in mind this basic rule: Isolate sensitive electronic devices from power-hungry devices whenever possible.
Sensitive electronic devices include:
- Computers and modems
- Servers
- Fax machines
Power-hungry devices include:
- Laser printers
- Photocopiers
Wiring and grounding issues
If your building isn’t wired to support office equipment, you’re likely to encounter power quality problems over time. In general, all electronic products and sensitive equipment benefit from dedicated branch circuits that are sized and installed to meet sensitive load recommendations.
Is your equipment vulnerable to these common culprits? Read the questions below and learn common causes of power quality problems.
1. Has your building’s wiring been modified over the years by electrical contractors?
- Wiring errors are the most common source of power quality problems. Most result from a violation of the National Electric Code.
2. Have ground conductors been routed from the electrical panel to each outlet?
- The National Electric Code allows use of the conduit system as ground reference for office equipment. But over time, the conduit connections deteriorate, which causes equipment to operate unreliably. Ground conductors minimize the problem.
3. Are the circuits that serve your computers also used to operate foot warmers, space heaters, microwave ovens or photocopiers?
- These items draw a lot of electricity, causing problems with computers.
4. Does the heating, ventilation and air conditioning system use the same electrical panel as your computers?
- Your risk of problems is even greater if you use a UPS because the UPS will react to the voltage changes caused by frequent cycling of this equipment. This runs the UPS battery down, reducing your protection.
5. Have you located your office equipment more than 50 feet from your electrical panel without increasing circuit conductor size?
- You may have lower voltages than normal.
6. Do you use extension cords longer than 6 feet to power office equipment?
- You should directly connect all equipment to a receptacle. Extension cords reduce available voltage.
7. Do you have an elevator or use an air compressor in your office environment?
- Electrical loads for elevators and air compressors should be separated from other office equipment.
8. Do you have light dimmers or overhead fluorescent lights (electrical ballast) powered from the same electrical panel as office equipment?
- They should be on separate panels.
9. Do more than 50 percent of your office’s electrical loads come from office equipment such as copy machines, laser printers, computers or fluorescent lights?
- This type of office equipment can distort voltage, resulting in equipment problems. Add additional branch circuits to serve these loads.
10. Do tenants in other parts of your building operate industrial process equipment?
- Industrial equipment can cause power quality problems.
Solutions to power problems in your office
Click here to view our chart with solutions to common power quality problems in an office environment.
Facility FAQ
Look here for answers to your power quality questions.
Can’t find what you’re looking for? Call the PGE power protection experts at: 503-736-5750 or 800-270-7016 or e-mail us.
Q. One of the 200-amp circuit breakers that serve a compressor has tripped several times. An electrician was unable to find any overload problems with the circuit breaker and thought it was probably due to harmonics. What can be done to fix the problem?
- Harmonics is a complex subject and when it causes circuit breakers to keep tripping, it's a nuisance. Harmonic currents are caused by certain types of equipment that draw current intermittently while running. Harmonic currents flow from the load, through the circuit breaker, and into PGE’s system. If the circuit breaker is tripping because of harmonics, it may be defective, or you may require a different type of breaker that is not sensitive to harmonics.
Harmonics are sometimes blamed when a circuit breaker that is protecting a compressor trips. However, if a compressor is pulling more than 80 percent of its nameplate capacity for an extended period of time, it will, in fact, overload the breaker and trip. So a 200-amp circuit breaker should not have more than 160 amps per phase for any extended period of time.
Q. We have a small standby generator that supports our critical systems when we have a power outage. We also have small uninterruptible power supplies to support the loads until the generator starts. However, the UPS does not work correctly when the generator operates. Why not?
- Not all UPS operate correctly when served by a generator. You can adjust the sensitivity of some UPS units so they work correctly with a small generator. Alternatively, it may be necessary to install better controls on the generator before the two can work together. Some generators do not have quality voltage and frequency regulation, while others cause too much voltage distortion. Each of these problems can cause some UPS systems to cycle their battery until it is depleted. Be sure to carefully review the specifications of any UPS you want to operate with a generator to ensure they will work together.
Q. We recently lost some control cards in one of our machines that has surge suppression. The repair technician told us the failure was due to surge damage. How can this be true?
- Losing some control cards due to surge damage may indicate inadequate surge suppression or improper installation.
Another common cause of failure for control cards is inadequate or incorrect grounding of the control card system. Wiring errors can lead to failures even if surge protection is available. Call the PGE power protection experts for assistance at 503-736-5750 or 800-270-7016, or e-mail us.
Q. One of our large three-phase motors keeps tripping. An electrician told us the motor is not drawing the same amount of current on each phase and something must be wrong with the service from PGE. What can be done?
- The PGE specification for voltage imbalance measured at your main service is 3 percent or less. Generally, we are below 2 percent. If the voltage is imbalanced it causes current imbalance in three-phase loads. And if there isn’t an equal load on each phase, the voltage imbalance can increase at different locations within your facility. If you think the voltage imbalance is higher than it should be, call the PGE power protection experts at 503-736-5750 or 800-270-7016, or e-mail us and ask us to measure your voltage.
Q. We have several variable frequency drives that frequently trip during the week. This usually occurs between 5 and 6 a.m. Do you know why this is occurring and what we can do to prevent it?
- If a VFD trips early in the morning, it may be that it is sensitive to capacitor switching transients. PGE turns the capacitor banks on and off at the substations to support our customer load requirements. Some brands of drives (15 HP and smaller) are sensitive to this one cycle disturbance; newer, larger drives are not as susceptible. The most cost-effective way to reduce this type of nuisance tripping is to install line reactors.
Q. Every time a fault occurs our variable frequency drives trip off line. What can be done to prevent this from occurring?
- Most faults are single-phase event, and most VFDs can ride through single-phase sags even when the voltage drops to almost zero. Unfortunately, the drive’s control circuit may not be able to handle such an event; a minor voltage sag on the control circuit can cause shutdown. There are many ways to solve this problem, but the two most cost-effective solutions are: 1) support the control circuit with an uninterruptible power supply, and 2) replace “weak link” control components with components that are less sensitive to sags. This may involve replacing only a few “ice cube&148; relays. To find out more, call the PGE power protection experts at 503-736-5750 or 800-270-7016 or
e-mail us.
Q. We added variable frequency drives to some of our motors. Now they seem to be failing much sooner than expected. Can you explain this?
- Adding VFDs to your existing motors is a good way to reduce your energy usage and have better control of your motors. However, it can lead to early failure of motors that are not designed to operate from a VFD. An inverter rated motor is one that is designed to operate correctly with a VFD. Motors that are not rated for use with a VFD can still be used with a drive, but additional mitigation steps are necessary to prevent early failure of the motor. To learn more, call the PGE power protection experts at 503-736-5750 or 800-270-7016 or e-mail us.
Facility Concerns
Different types of large commercial and industrial facilities face similar power quality problems. Here are 10 of the most common concerns:
1. Grounding sensitive machinery
Some equipment manufacturers specify that the power grounding system should not be used for sensitive machinery, such as computer numerical control machines. In fact, some CNC manufacturers designate the installation of a ground rod, separate from the power grounding electrode system, to serve as their ground reference. This type of installation, however, is a violation of the National Electric Code and under certain conditions can lead to personal injury and equipment damage.
2. Accommodating large motor loads
Starting a motor can require so much electricity that it reduces the voltage for all the other loads that share the same transformer. This can cause many problems, including control systems malfunctioning, high intensity discharge lighting failures and dimming lights. You can reduce the motor load by using soft start controllers and adjustable frequency drives.
3. Correct installation of adjustable speed drives
If you install adjustable speed drives, it's likely you'll experience nuisance trips and increase harmonic distortion unless you install line reactors or isolation transformers at the same time.
4. Avoiding electrical noise
Arcing loads, such as welders and electronic lighting, can create electrical noise that affects TVs, radios and telecommunications equipment. Enhanced grounding and bonding can increase the immunity to electrical noise.
5. Dealing with older adjustable speed drives
Older adjustable speed drives are often sensitive to minor power disturbances. Some newer drives feature stronger immunity capabilities. Call the PGE power protection experts about the installation of a new drive at 503-736-5750 or 800-270-7016. We can share important steps in specifying new drive performance criteria to minimize your power quality problems.
6. Power factor correction
You may create rather than diminish power quality problems
when you combine power factor correction with harmonics-producing loads.
Call the PGE power protection experts at
503-736-5750 or 800-270-7016 or e-mail us to find out more.
7. Using neutral conductors
Shared neutral conductors often lead to power quality problems. For example, if three branch circuits share one neutral conductor, the conductor could be overloaded. You can minimize problems by reducing load and using separate neutral conductors for each circuit.
8. Serving sensitive equipment
Large facilities often use long branch circuits to serve sensitive equipment locations. But, even with minor loads that cycle on and off, this can cause equipment to malfunction. To increase reliability, install a transformer near all sensitive equipment locations.
9. Increasing UPS reliability
If you use a UPS system to protect critical loads from power disturbances, make sure the battery string is good. Install battery monitoring systems and provide proper maintenance to increase the reliability of UPS systems.
10. Ensuring generator reliability
It is important to test your standby generator with building loads on a monthly basis to confirm that it is operating properly. By performing this type of regular testing, you can spot potential problems in advance and ensure that equipment will be in working order at critical times.
|
|
