VARNISH DIPPING PROCESS
Conventional dipping is used in the reconditioning of a quality winding. After cleaning and testing, the winding is preheated to 125-150˚F to enable optimum penetration of the varnish into the windings, as well as the stator laminations.
Motors that have been previously dipped or VPI treated will not see a great deal of winding penetration. The heated winding is submerged in varnish and allowed to sit until all air bubbles cease to rise, indicating that all the air is out of the part. The winding is then raised above the varnish level and allowed to drain until no dripping of the excess varnish is observed.
We use EB 920, a high temperature electrical insulating varnish that exceeds Class H (180 ˚C) with a thermal rating up to 240 ˚C. It is a solvent-based polyester varnish which is thinned with Xylol thinner to proper viscosity. A sample of the varnish is routinely sent to the manufacturer for analysis to ensure our Customers the best possible product.
The purpose of dipping is to reinsulate the winding by providing an extra surface coating over the preexisting coating, which may have degraded, cracked, or worn due to the expansion and contraction that occurs during normal use.
FULL IN HOUSE MACHINE SHOP
SMTCL AH130 Boring Mill
The Machine Shop is responsible for designing, repairing, or fabricating components to OEM condition or better.
Our full complement Machine Department facilitates all aspects of precision repair and fabrication of component parts for electric motors, pumps, shafts, housings, etc.
Our large Monarch Lathe (pictured below) is mounted on a vibration isolation pad, and is used for precision grinding of fits and seats.
Lodge & Shiply Lathe - 25" Swing x 120" Long
Monarch Lathe - 60" Swing x 228" Long
VACUUM PRESSURE IMPREGNATION PROCESS (VPI)
Our 7’ diameter Vacuum Pressure Impregnation (VPI) system has the ability to process up to 5000 HP Motors. It is a system in which vacuum and pressure are used to assist the penetration of liquids into various materials and devices. It is often used to impregnate electrical apparatuses with insulating resins (electrical varnishes), because it can provide a virtually void free insulation with only one VPI cycle. VPI produces top quality insulation systems, better mechanical strength, environmental protection, and superior chemical, moisture, and corona resistance.
Tram utilizes John C. Dolph’s CC1118LV one part, low viscosity, thixotropic (materials that liquefy or flow when agitated and return to a thick gel like consistency when allowed to rest), impregnating epoxy compound. This compound is unique for use where higher voltage, low corona, chemical resistance, and electrical insulation properties at elevated temperatures are required. Motors processed with one cycle in CC1118LV have passed Navy total submersion testing per MIL-M-17060E. After this process, the electrical apparatus is placed in the bake oven to cure at 302 degrees Fahrenheit.
COMPUTERIZED DYNAMOMETER LOAD TESTING
The load test center consists of a 1500 kva power supply, a motor efficiency panel, and an AW-900 and AW-600 water-cooled hydraulic dynamometer. Testing electric motors for operational efficiency and ability to create rated horsepower at rated speed within the electrical ratings of the motor is paramount to certified operational integrity.
Using a kilowatt meter, at any percentage of load on the motor, the efficiency of the motor can be determined. One horsepower is the equivalent of 746 watts. Using this factor and recording the wattage draw at any given horsepower, the efficiency of the motor can be calculated.
A dynamometer is a device used for measuring rotational force or power, and is used specifically to test motors under conditions of mechanical load. The mechanical force of rotation (torque) is measured by a load cell transducer in the dynamometer and is expressed in foot/pounds. A transducer transforms a mechanical signal into an electrical one. The rotational speed in RPMs is measured in the dynamometer by an electronic tachometer. Data from these two measurements during a motor test is fed into a computer, which calculates the horsepower produced by the motor at various load values. The dynamometer is capable of handling 20 HP through 900 HP with a 3200 ft./lb. rated torque shaft.
DC MAGNETIC ANALYZING
The electromagnetic analyzer is a multifunction device used primarily in DC motor and generator repair to locate the inductive neutral of the brushes. It is also used to test armature windings (bar to bar) and to verify correct lead identification in DC motor and generator fields, along with locating faulty or shorted field windings by measuring relative magnetic flux density and resistance.
Vibration analysis is a very important step in any maintenance program. This is true even in highly monitored installations. Monitoring provides an indication of overall vibration levels. It does not, however, give an indication of cause. Only analysis can provide this information. The first step is using our vibration analyzer to evaluate the condition of your rotating equipment. Tram evaluates the amplitude measurement of the overall level and frequency of the machine's predominant vibration signature. This gives an indication of the overall condition. Then comes frequency analysis. Frequency analysis is the process of recording all the frequency components of the vibration or imbalance. For Example, a rough bearing may cause some imbalance in a rotating mass, but loose material build up in the rotor may also cause imbalance at a different frequency. Coupler misalignment or worn belts may cause yet another frequency of imbalance. Through frequency analysis, these problems can be identified and corrected, often times with the motor still in position, saving you time, money, and hassle.
The SKF Microlog Analyzer GX series (pictured left) is a next generation data collector/analyzer. It is a full-featured monitoring/analysis tool that includes vibration signals and process variables over a range of 10 CPM to 2,400,000 CPM. It utilizes the latest advances in analog and digital electronics to provide both speed and accuracy in the data collection process. Utilizing SKF’s Aptitude and Prism 4 software, the data collected can be manipulated and studied for all or any part of any concerning spectra, enabling our technician to determine the root cause of the problem.
COMPUTERIZED DYNAMIC BALANCING
At Tram, we utilize three models of dynamic balancing equipment that were manufactured by the Industrial Engineering and Machine Co. of Atlanta, Georgia (IEM). Dyna-Bal is the brand name. The first unit is rated to balance a 2500 lb. rotating mass. The second can balance a mass of up to 10,000 lbs., while the third will safely balance a 15000 lb. rotating mass. Our balancing machines are designed to indicate pure static, pure dynamic, or any combination of these. The question of precision balance is entirely controlled by the work piece, condition of journals, and deflection or whip condition on flexible type rotors. It is just as easy to affect complete balance down to a few micro inches, as it is to do a rough commercial balancing job. As long as the journals or bearings of the work piece are properly finished and the piece is free from whip or deflection, this equipment is capable of extreme sensitivity, down to 0.000002 inches.
With some understanding of vibration analysis, and use of these principles, we can balance a rotating apparatus in our facility before assembly of the repaired unit. All rotational components of a given piece of equipment are installed on the shaft in their respective positions and balancing is performed. “Dynamic Balancing” is balancing which is performed with the unit rotating at rated speed or at some harmonic of the unit’s rated speed. Unlike “Static Balancing,” which relies upon the heaviest side of mass to turn down with gravity while resting on an anti-friction rotating weigh, Dynamic balancing can produce an actual reading of the sensing transducer and computer module, and pinpoint the exact location of the mass displacement.
With the use of a high intensity strobe light or photo eye, the exact angle of displacement is identified, and depending on the RPMs the unit is being analyzed at, the proper amount, and location of corrective weight, can be added or removed from the rotating component. All assemblies repaired at our facility are balanced to within NEMA specifications for the RPM rating of the unit. Specific customer balance specifications are welcome, and Tram will accommodate any special requirements. Special precision balancing is performed routinely on these apparatuses.
SURGE COMPARISON TESTING/ADVANCED WINDING ANALYSIS
The Baker Advanced Winding Analyzer (AWA) is used to detect winding faults and defective insulation in coils, motors, generators, and transformers. The surge tester can detect turn-to-turn, coil-to-coil, and phase-to-phase short circuits, opens, grounds, misconnections, and incorrect turn counts.
Tram uses the Baker Advanced Winding Analyzer IV (AWA IV), along with the PP30 Power Pack (30 kV). The AWA IV supports all major electrical tests such as Surge Comparison, Polarization Index, DC Hi Pot, Megger, and Winding Resistance Testing. It also gives us the opportunity to provide our customers with high quality reporting and trending of their motors operational integrity.
The PP30 Power Pack is a high impulse generator used to test very large high voltage windings. The AWA IV combined with the PP30 Power Pack expands Tram’s capabilities for the most efficient, accurate testing of windings.
AWA IV has the capability of reaching a target voltage of 9300V surge on a 2500 HP 4160V motor. With the combination of the AWA IV and the PP30 Power Pack, the capabilities can reach a target voltage of 29kV surge on an 8500 HP 13.8kV motor.
ELECTRIC MOTOR REWIND
The Winding Department is responsible to rewind both AC and DC electric motors using no less than class H 180 degree Centigrade rated insulation material. We utilize two Samatic winding machines for efficiently manufacturing coils. Although winding data is recorded on every motor, the winding engineering design data is verified prior to winding coils.
COMPUTERIZED COIL WINDING
The winding data of every motor we have ever processed is stored in our winding databases for AC, DC or Transformers/Coils. This data can be uploaded to our Samatic machine and used to create precise winding patterns for your equipment.
The technician sets up the machines with the data, supplies the machine with the required magnet wire quantities and sizes, fits the proper insulation sleeves onto the wire run, and the machine then automatically winds the coil groups to those parameters. Each coil is exactly the same size, and wound much more uniformly than can be done by human hand, which decreases insertion time and increases motor performance because of a more symmetrical winding layout.
WELDING AND FABRICATION
Our Welding & Fabrication Department is responsible for designing, repairing, and fabricating components to OEM condition or better.
The welding department welds many different materials, including steel, cast iron, aluminum, and copper (as in commutator bars).
Welding services include shield metal arc welding (SMAW), gas tungsten arc welding (GTAW), gas metal arc welding (GMAW), and flux core arc welding (FCAW).
As we repair all types of components for electrical apparatuses, we use an induction heating system where heat is created electromagnetically in the metal rather than by surface heating. Heat is induced in the metal prior to welding by placing it in an alternating magnet field created by current flow in the water-cooled induction heater cables. The induction cables are wrapped around the part to be welded and do not themselves heat up, but create eddy currents inside the part, which generate heat. This allows for more precise and uniform heating in the part.
POWER DISTRIBUTION SERVICES
The Power Distribution Department is responsible for the repair and calibration of circuit breakers, repair and reconditioning of welders and generators, as well as the remanufacturing of power distribution centers and sectionalizing switches.
All products are completely disassembled, cleaned, and painted. Individual components are bench tested and repaired before reassembly and testing. Our Customers are welcome to inspect any phase of reconditioning or remanufacturing as the job is progressing, as well as taking part in the final testing.
Multi-AMP Tester (pictured left)
The Multi-Amp Tester ranges from 0 to 25,000 Amps. This allows us to pass current through monitoring and limiting devices such as relays and breakers. With this tester, we are able to simulate field situations and adjust current limits as well as time delays to prevent nuisance tripping while ensuring proper trip values.
Making the Invisible Visible
Virtually everything in our world emits infared radiation. While neither the naked eye nor a digital camera can see the infared spectrum, you feel its effects in the form of heat from sunlight, electrical equipment, and industrial process.
Thermal imaging is a non-contact technology used to aid in identifying potential electrical, mechanical, or process problems from a safe distance.
It allows us to scan moving, elevated, and high temperature surfaces without getting too close. It can quickly scan large surface areas for temperature differences that often indicate that a problem exists, or that a failure could be imminent. It also detects heat patterns or temperature changes in objects. These changes allow us to discover problems prior to costly unplanned downtime, or to monitor developing problems so maintenance can be scheduled in advance prior to costly breakdowns.
ULTRASONIC FLAW DETECTION
Our Site Scan Ultrasonic test unit is used to inspect motor and pump shafts for voids, cracks, or other flaws both radially and axially. It is also used to detect cracks or flaws in housings and water cooling jackets on permissible motors. It can be used on most materials - steel, brass, aluminum, and copper.
Ultrasonic testing is a safe, non-destructive test method used to detect flaws and breaks in shafts.
Ultrasonic waves give us the ability to “see through” solid/opaque material and detect surface and internal flaws without adversely affecting the material.
IN-DEPTH REPAIR REPORTING
We provide our customers with a repair report for every piece of equipment upon completion of repairs, which includes nameplate information, part numbers for replacement parts, mechanical and electrical failure analysis, description of corrective repairs performed, and initial and final test result information.
Copies of the actual test results from our production equipment are available upon request. Final testing and reporting is easily customized to specific Customer requirements and/or specifications.
A Permissiblilty Report is provided to our customers for every permissible motor. Underground mining requires extensive use of electrical face equipment. Permissible machines require the use of explosion proof enclosures. These enclosures are designed and tested to withstand internal explosions of methane mixtures, avoiding damage to the wall or cover of the enclosure, and ignition to the outside of the enclosure.
In order for a piece of equipment to be permissible, it must meet all requirements set forth by federal law, which not only includes mechanical integrity of the component, but the cable, conduit, and the documentation of said permissibility through the use of approval plates with MSHA assigned approval number.