Overload Relays
Todays deals on Overload Relays?
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30 FITS SIEMENS OVERLOAD RELAY OR-3UA6600-3B 125-200A $4,999.99 |
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WESTINGHOUSE MORA2MAE MODULAR OVERLOAD RELAY 46A ***NIB*** $3,399.00 |
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24 NEW FITS SIEMENS OVERLOAD RELAY 3UA6600-3D 200-320A $3,299.99 |
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WARD LEONARD OVERLOAD RELAY PART # 1321496-10 NSN: 5945-00-118-8924 26524.204-1 $2,700.00 |
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48 NEW FITS SIEMENS OVERLOAD RELAY 3UA6200-3K 120-150A $1,899.99 |
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48 NEW FITS SIEMENS OVERLOAD RELAY 3UA6200-3L 135-160A $1,899.99 |
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48 NEW FITS SIEMENS OVERLOAD RELAY 3UA6200-3M 150-180A $1,899.99 |
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48 NEW FITS SIEMENS OVERLOAD RELAY 3UA6200-3J 110-135A $1,899.99 |
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48 NEW FITS SIEMENS OVERLOAD RELAY 3UA6200-3H 90-120A $1,899.99 |
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12 NEW FITS SIEMENS OVERLOAD RELAY 3UA6600-3D 200-320A $1,699.99 |
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Furnas three phase solid state overload 948CA31B $1,249.99 |
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AB Electronic Overload Relay 193-EC3GF (193EC3GF) NIB！ $1,062.00 |
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ALLEN BRADLEY MAGNETIC OVERLOAD RELAY 810-A09C 810A09C 1RP OPEN 28A 600V $1,000.00 |
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ALLEN BRADLEY MAGNETIC OVERLOAD RELAY 810-A14C 810A14C 72A 600V w/ 810-N9B $1,000.00 |
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Allen-Bradley 810-A04A Magnetic Overload Relay $1,000.00 |
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DIRECT FACTORY SHIPPMENT 100 REPLACEMENT OVERLOAD RELAY FITS LG GTH-12 1-1.6A OR $999.99 |
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DIRECT FACTORY SHIPPMENT 100 REPLACEMENT OVERLOAD RELAY FITS LG GTH-12 1.6-2.5A $999.99 |
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DIRECT FACTORY SHIPPMENT 100 REPLACEMENT OVERLOAD RELAY FITS LG GTH-9,12 7-10A $999.99 |
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DIRECT FACTORY SHIPPMENT 100 REPLACEMENT OVERLOAD RELAY FITS LG GTH-9,12 5.5-8A $999.99 |
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DIRECT FACTORY SHIPPMENT 100 REPLACEMENT OVERLOAD RELAY FITS LG GTH-9,12 9-13A $999.99 |
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DIRECT FACTORY SHIPPMENT 100 REPLACEMENT OVERLOAD RELAY FITS LG GTH-9,12 7-10A $999.99 |
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24 NEW FITS SIEMENS OVERLOAD RELAY 3UA6200-3K 120-150A $999.99 |
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24 NEW FITS SIEMENS OVERLOAD RELAY 3UA6200-3L 135-160A $999.99 |
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24 NEW FITS SIEMENS OVERLOAD RELAY 3UA6200-3M 150-180A $999.99 |
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24 NEW FITS SIEMENS OVERLOAD RELAY 3UA6200-3J 110-135A $999.99 |
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24 NEW FITS SIEMENS OVERLOAD RELAY 3UA6200-3H 90-120A $999.99 |
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WARD LEONARD OVERLOAD RELAY TYPE N147 PART # 1321494-4 NSN: 5945-00-918-1273 $975.00 |
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AB Electronic Overload Relay 193-EC2EE (193EC2EE) NIB！ $960.00 |
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AB Electronic Overload Relay 193-EC2DE (193EC2DE) NIB！ $960.00 |
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AB Overload Relay 193-EC1DE (193EC1DE) NIB $929.00 |
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NEW NIB ALLEN BRADLEY 810A-25A MAGNETIC OVERLOAD RELAY $899.00 |
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6 NEW FITS SIEMENS OVERLOAD RELAY 3UA6600-3D 200-320A $899.00 |
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AB Electronic Overload Relay 193-EC2CD (193EC2CD) NIB！ $850.00 |
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AB Electronic Overload Relay 193-EC2AB (193EC2AB)NIB！ $791.00 |
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Electric Motor Starter W/ overload Relay & Reset instld $617.50 |
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1 NIB WESTINGHOUSE FT23P-36 OVERLOAD RELAY Q5-3 $649.99 |
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AB Electronic Overload Relay 193-EC1CB (193EC1CB) NIB！ $654.00 |
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WESTINGHOUSE MORA1MAE MODULAR OVERLOAD RELAY 1373D02G34 $599.99 |
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ALLEN BRADLEY 193-EENH 193EENH OVERLOAD RELAY NEW NIB $586.50 |
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SQUARE D THERMAL OVERLOAD RELAY # 9065 / AGO – 1L SER A $568.00 |
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CUTLER-HAMMER C310FNA3 SOLID STATE OVERLOAD $572.87 |
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Allen Bradley 810-A02C Magnetic Overload Relay 600V 3A $549.95 |
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MISC. LOT OF 5: EATON STARTER, OVERLOAD RELAY & AUX. CONTACT (SEE PHOTOS) L27-3 $550.00 |
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Westinghouse A201K2CX Motor w/ BA23A Overload Relay $499.00 |
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NEW ALLEN BRADLEY 193-EA2GB OVERLOAD RELAY CLASS 20 12-32 AMPS 1 N.O & 1 N.C. $549.99 |
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SQUARE D CC 74.6, OVERLOAD RELAY THERMAL UNIT, LOT OF (5) NIB $39.00 |
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ALLEN-BRADLEY 825-MCM630 OVERLOAD Ie= 160…630A 1000V 50/60Hz SER.A QUANTITY!!! $479.00 |
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1 SIEMENS 3TF50 CONTACTOR w/ 3UA60 OVERLOAD RELAY L6 $495.00 |
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Allen Bradley Overload Relay Cat# 592-A2NF $499.99 |
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TA25DU QTY 15 ABB THERMAL OVERLOAD RELAYS $499.95 |
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ALLEN BRADLEY 193-EC2ZZ OVERLOAD RELAY WITH INSTRUCTION MANUAL NEW IN BOX $475.00 |
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GENERAL ELECTRIC CR5882-3F OVERLOAD RELAY NSN: 5945-00-399-0546 $495.00 |
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Furnas ESP100 14IS+32A* Size 3 1/2 75HP @ 460V 550-600V Coil With Overload Relay $465.50 |
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Westinghouse Thermal Overload Relay AA43P 3 Pole Size 4 $472.49 |
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SYLVANIA 28UT3-68 INVERSE TIME OVERLOAD RELAY $445.00 |
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SQUARE D 8536-D0-1-A/8536D01A OVERLOAD RELAY ***XLNT*** $434.00 |
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ALLEN-BRADLEY 509-BOD with 592-EC1CC OVERLOAD RELAY $450.00 |
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NEW CUTLER HAMMER C306NN3 OVERLOAD RELAY 3 POLE $424.99 |
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ALLEN BRADLEY 193-EC2CD 193EC2CD OVERLOAD RELAY NEW NIB $429.25 |
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ALLEN-BRADLEY 193-B1N6 OVERLOAD RELAY SER. B $374.99 |
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ALLEN-BRADLEY CURRENT OVERLOAD MONITOR RELAY 193-EC3ZZ $400.00 |
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NEW ALLEN BRADLEY 193-EC2DD OVERLOAD RELAY SOLID STATE $400.00 |
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CUTLER HAMMER MOTOR SAVER ELECTRONIC OVERLOAD RELAY # E777-575 100% NEW #2 $400.00 |
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CUTLER HAMMER MOTOR SAVER ELECTRONIC OVERLOAD RELAY # E777-575 100% NEW #1 $400.00 |
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SIEMENS 3UA6600-3B* OVERLOAD RELAY 125-200A $354.99 |
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SIEMENS 80 AMP REVERSING CONTACTOR OVERLOAD ASSEMBLY 3RT10463AK60 3RB10461EB0 $379.99 |
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SQUARE D 9065SR410 NIB MOTORLOGIC SOLID STATE OVERLOAD RELAY $375.00 |
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SIEMENS GROUND FAULT RELAY OVERLOAD 3RB1246-1QG20 * NIB $343.99 |
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2 NEW SIEMENS MOTOR OVERLOAD RELAYS MODEL 3VU1600-0MH00 $369.99 |
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ALLEN BRADLEY 815-DOV169 OVERLOAD RELAY NOS $365.00 |
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Allen Bradley Overload Relay 193-EPD180 600 VAC 3799 $349.99 |
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SQUARE D THERMAL OVERLOAD RELAY # 9065 / SAUO -1L , NEW $349.00 |
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ALLEN BRADLEY MODEL 193-EC1DD OVERLOAD RELAY NEW $350.00 |
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21011 NEW Allen Bradley 815-EOV4 Overload Relay 600VAC $341.25 |
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AN43P Westinghouse Thermal Overload Relay NEMA 4 3 POLE $329.99 |
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GE RT4N MANUAL/AUTO OVERLOAD RELAY ASSEMBLY 120-190AMP $325.00 |
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SQUARE-D MOTOR LOGIC PLUS II 9065 SP246 OVERLOAD RELAY $329.00 |
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Cutler-Hammer C310BNA3 Solid State Overload Relay Series A1 120VAC, 5MA Max. $324.98 |
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OTIS KONE THYSSEN ELEVATOR ALLEN BRADLEY INVERSE RELAY 162amps.DASHPOT OVERLOAD $325.00 |
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Siemens 3RB1253-0FG30 Electronic Overload Relay $334.56 |
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OTIS KONE THYSSEN ELEVATOR ALLEN BRADLEY INVERSE RELAY 162amps.DASHPOT OVERLOAD $315.00 |
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CASATI HINGE MACHINE MOTOR STARTER RELAYS OVERLOAD ALL CONTROLS TELEMECANIQUE $325.00 |
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Telemecanique Integral 32 Starter W/Overload Relay & Auxiliary Contact Block $325.00 |
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Telemecanique LR9 F 7379 Overload Relay LR9F7379 Motor Protection 300Amp-500Amp $220.01 |
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Moeller DILM115 Contactor w/ ZB150-125KK Overload Relay $315.00 |
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Allen Bradley #815-E0V16 Overload Relay 600V Series K $299.00 |
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ALLEN BRADLEY # 810-A06C (SER)B MAGNETIC OVERLOAD RELAY $299.99 |
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NEW ALLEN BRADLEY MOTOR STARTER OVERLOAD MODEL 509-B0D $299.99 |
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Overload Relay CEP7-EEGE FREE SHIPPING $312.00 |
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Overload Relay CEP7-EEGE FREE SHIPPING $312.00 |
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Westinghouse AN33A thermal overload relay 3pole size 3 for starter mounting $300.00 |
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CUTLER-HAMMER OVERLOAD RELAY STARTER; CAT # C306NN3, USED, GOOD CONDITION $300.00 |
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SYLVANIA 28UT3-500 DC INVERSE TIME OVERLOAD RELAY ***NNB*** $299.00 |
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KLOCKNER-MOELLER Z4-180-CNA THERMAL OVERLOAD RELAY 140-180A $270.00 |
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1 NIB WESTINGHOUSE AA33P OVERLOAD RELAY Q5-3 $289.99 |
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Allen Bradley 193-EC2ZZ Overload Relay $289.95 |
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Klocker Moeller Thermal Overload Relay ZWA-6.3 $300.00 |
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NEW IN BOX, CUTLER-HAMMER AA33P THERMAL OVERLOAD RELAY $300.00 |
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CUTLER HAMMER OVERLOAD RELAY #C306GN3B MAN/AUTO 3 POLE 75AMPS NEW $275.00 |
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Furnas Starter W/Overload Relay 14FS+32A* Series B, D74694-007 Series A, 14FS32A $300.00 |
Overload Relays Questions
Transformer Faults and Detection
In order to maximize the lifetime and efficacy of a transformer, it is important to be
aware of possible faults that may occur and to know how to catch them early. Regular
monitoring and maintenance can make it possible to detect new flaws before much damage
has been done.
The four main types of transformer faults are:
1. Arcing, or high current break down
2. Low energy sparking, or partial discharges
3. Localized overheating, or hot spots
4. General overheating due to inadequate cooling or sustained overloading
These faults can all lead to the thermal degradation of the oil and paper insulation
within the transformer. One way to detect them is by evaluating the quantities of
hydrocarbon gases, hydrogen and oxides of carbon present in the transformer. Different
gases can serve as markers for different types of faults. For instance,
* Large quantities of hydrogen and acetylene (C2H2) can indicate heavy current
arcing. Oxides of carbon may also be found if the arcing involves paper insulation.
* The presence of hydrogen and lower order hydrocarbons can be a sign of partial
discharge
* Significant amounts of methane and ethane may mean localized heating or hot spots.
* CO and CO2 may evolve if the paper insulation overheats; which can be a result of
prolonged overloading or impaired heat transfer.
Techniques to Detect Faults
Techniques for finding faults:
* Buchholz Relay safety device
* Dissolved gas analysis
* Tests to detect oil contaminants and oil quality
Techniques to detect transformer faults include the Buchholz Relay safety device,
dissolved gas analysis (DGA) tests and a range of tests for detecting the presence of
contaminants in the oil, as well as for measuring indicators of oil quality such as
electric strength and resistivity.
* Buchholz Relay
A Buchholz Relay is also called a gas detection relay. It is a safety device
generally mounted at the middle of the pipe connecting the transformer tank to the
conservator. A Buchholz Relay may be used to detect both minor and major faults in the
transformer.
This device functions by detecting the volume of gas produced in the transformer
tank. Minor faults produce gas that accumulates over time within the relay chamber. Once
the volume of gas produced exceeds a certain level, the float will lower and close the
contact, setting off an alarm.
Major faults can cause the sudden production of a large quantity of gas. In this
case, the abrupt rise in pressure within the tank will cause oil to flow into the
conservator. Once this is detected the float will lower to close the contact, which
causes the circuit breaker to trip or sets off the alarm.
* Dissolved gas analysis (DGA)
Dissolved gas analysis, or DGA, is a test used as a diagnostic and maintenance tool
for machinery. Under normal conditions, the dielectric fluid present in a transformer
will not decompose at a rapid rate. However, thermal and electrical faults can accelerate
the decomposition of dielectric fluid and solid insulation. Gases produced by this
process are all of low molecular weight, and include hydrogen, methane, ethane,
acetylene, carbon monoxide and carbon dioxide. These gases will dissolve in the
dielectric fluid. Analyzing the specific proportions of each gas will help in identifying
faults. Faults detected in such a way may include processes such as corona, sparking,
overheating and arcing.
Abnormal functioning within a transformer can be caught early by studying the gases
that accumulate within it. If the right countermeasures are taken early on, damage to
equipment can be minimized.
*
Other oil tests
Other oil tests used to detect faults include acidity tests, electric strength
tests, fiber estimation tests, color tests, water content tests, Polychlorinated Biphenyl
Analysis (PCB) tests, furfuraldehyde analysis tests, metal in oil analysis tests and
resistivity tests.
o Acidity test: The acidity of transformer fluid should be monitored regularly.
High acidities can hasten the degradation of paper insulation and cause steel tanks to
corrode.
o Electric Strength: The electric strength of an insulating fluid is its
capacity to withstand electrical stress without failing. The lower the dielectric
strength of a fluid, the less it will be able to insulate. Transformer failure can result
if the dielectric strength drops too low.
o Fiber estimation: If fibers or other contaminants are present in a
transformer’s oil, they may reduce the oil’s electric strength. Wet fibers in
particular can be drawn into an electrical field, resulting in arcing. Passing polarized
light through an oil sample can make fibers and other sediments visible, making it
possible to estimate the fiber content of the sample. Sampling should be done carefully,
since both fibers and moisture may be picked up during the process of sampling itself.
o Color: Obvious changes in oil color (for instance, light oil abruptly growing
dark) may indicate deeper changes within the oil itself that need to be examined further.
o PCB Test: A Polychlorinated Biphenyl Analysis (PCB) test calculates the
concentration or presence of polychlorinated biphenyl within the oil. Capillary column
chromatography can be used for this process. While the presence of PCBs is not an
indication of oil quality, PCBS are a banned substance, no longer allowed in new liquid
filled transformers.
o Metal in oil analysis: The concentrations of various metals in a
transformer’s oil can be calculated by using methods such as atomic absorption
spectroscopy (AA) and inductive coupled plasma spectrometry (ICP).
o Furfuraldehyde Analysis: The concentration of furfuraldehyde in an oil sample
can be used as a measure of paper degradation. Furfuraldehyde is one of the byproducts of
paper degrading and growing weaker, a process which sets a natural limit on a
transformer’s life. Monitoring its concentration levels can help determine the remaining
service life of a transformer.
o Moisture: Excess moisture in the oil can cause the oil’s electric strength to
plummet, leading to transformer failure. It is therefore very important to monitor
moisture levels in the transformer.
o Resistivity Test: High resistivity indicates low levels of free ions and ion
-forming particles, as well as low levels of conductive contaminants. Resistivity tests
are generally carried out at ambient temperature. It can also be useful, however, to
carry out tests at much higher temperatures, the results of which can be compared to
results at ambient temperature.
*
Other oil tests
Other oil tests used to detect faults include acidity tests, electric strength
tests, fiber estimation tests, color tests, water content tests, Polychlorinated Biphenyl
Analysis (PCB) tests, furfuraldehyde analysis tests, metal in oil analysis tests and
resistivity tests.
o Acidity test: The acidity of transformer fluid should be monitored regularly.
High acidities can hasten the degradation of paper insulation and cause steel tanks to
corrode.
o Electric Strength: The electric strength of an insulating fluid is its
capacity to withstand electrical stress without failing. The lower the dielectric
strength of a fluid, the less it will be able to insulate. Transformer failure can result
if the dielectric strength drops too low.
o Fiber estimation: If fibers or other contaminants are present in a
transformer’s oil, they may reduce the oil’s electric strength. Wet fibers in
particular can be drawn into an electrical field, resulting in arcing. Passing polarized
light through an oil sample can make fibers and other sediments visible, making it
possible to estimate the fiber content of the sample. Sampling should be done carefully,
since both fibers and moisture may be picked up during the process of sampling itself.
o Color: Obvious changes in oil color (for instance, light oil abruptly growing
dark) may indicate deeper changes within the oil itself that need to be examined further.
PCB Test: A Polychlorinated Biphenyl Analysis (PCB) test calculates the
concentration or presence of polychlorinated biphenyl within the oil. Capillary column
chromatography can be used for this process. While the presence of PCBs is not an
indication of oil quality, PCBS are a banned substance, no longer allowed in new liquid
filled transformers.
o Metal in oil analysis: The concentrations of various metals in a
transformer’s oil can be calculated by using methods such as atomic absorption
spectroscopy (AA) and inductive coupled plasma spectrometry (ICP).
o Furfuraldehyde Analysis: The concentration of furfuraldehyde in an oil sample
can be used as a measure of paper degradation. Furfuraldehyde is one of the byproducts of
paper degrading and growing weaker, a process which sets a natural limit on a
transformer’s life. Monitoring its concentration levels can help determine the remaining
service life of a transformer.
o Moisture: Excess moisture in the oil can cause the oil’s electric strength to
plummet, leading to transformer failure. It is therefore very important to monitor
moisture levels in the transformer.
o Resistivity Test: High resistivity indicates low levels of free ions and ion
-forming particles, as well as low levels of conductive contaminants. Resistivity tests
are generally carried out at ambient temperature. It can also be useful, however, to
carry out tests at much higher temperatures, the results of which can be compared to
results at ambient temperature.
To know more about <a href=”http://www.pacificcresttrans.com/home.html”>Liquid filled
distribution transformers</a> check out Pacific crest transformers website.
http://www.pacificcresttrans.com/home.html
About the Author
mike dikinson-contributing writer for Pacific crest transformers.
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