Plastic Thermoforming

Plastic thermoforming is a process of manufacturing where a plastic sheet is heated to a flexible temperature, molded to a specific shape, and trimmed to create an end product. Complex and high-volume plastic thermoforming applications can manufacture thousands of finished products per hour depending on machine, mold size, and the size of the units being formed.
Thin-gauge plastic thermoforming is primarily used to manufacture products for food, medical, and other related industries. Thick-gauge plastic thermoforming is used to manufacture vehicle doors, vehicle dash panels, refrigerator liners, utility vehicle beds, plastic pallets, and other related products.

Thin-gauge plastic thermoforming uses plastic sheets that are fed from a roll or from an extruder into a group of indexing chains that incorporate pins to puncture the sheet and move it through an oven for heating to a molding temperature. The hot sheets are then indexed into a form station where a partner mold and pressure-box close on the sheet, with vacuum then applied to remove trapped air and to pull the material into the mold along with pressurized air to form the plastic to the detailed shape of the mold.

After the form cycle, a gust of reverse air pressure is propelled from the vacuum side of the mold as the form tooling opens to break the vacuum and assist the formed parts off the mold. Stripper plates may be utilized on the mold as it opens for ejection of more precise parts or those with negative-draft, undercut areas. The plastic sheet containing the formed parts then indexes into a trim station on the same machine, and a die cuts the parts from the remaining sheet web, or indexes them into a separate trim press where the formed parts are trimmed. The sheet remaining after the formed parts are trimmed is usually wound onto a reel or fed into an inline granulator for recycling purposes.Most plastic thermoforming manufacturers recycle their wasted scrap by compressing in a baling machine or by feeding into a granulator and producing ground flake, for sale to reprocessing companies, or they re-use it in their own facility. Most scrap and wasted plastic from the thermoforming process is converted back into extruded sheet for forming again.

For plastic thermoforming equipment retrofitting, repair and replacement quotes, contact Precision Electric, Inc.

Eaton Drives Troubleshooting

Eaton drivestroubleshooting can be time consuming, so manufacturers tend to keep spare Eaton drives on hand for production lines that can’t afford downtime.When Eaton drivestroubleshooting cannot be resolved in the plant, technicians are known to send their Eaton VFD to the original equipment manufacturer or Eaton VFD repair centers for repair and replacement options. The original equipment manufacturer of Eaton drives and Eaton VFD repair centers usually only offer a replacement for failed drives, but this isn’t usually the most economical solution for manufacturers. Eaton also repairs failed drives but the lead-time for Eaton to repair their own drives is extensive and expensive.

When Eaton drivestroubleshooting leads to Eaton VFD repair, the repair process should be taken with extreme caution. Eaton VFD repair should only be performed by technicians who have required training and experience to work with electrical equipment. Precision Electric strongly recommends to consult an expert in the field when repairing and troubleshooting Eaton VFD equipment.The troubleshooting techniques for each brand of VFD can be unique, but the overall structure of troubleshooting always remains the same.The ultimate goal when performing Eaton drivestroubleshooting is to diagnose, repair and re-commission the unit as quickly as possible, and these are the steps that Precision Electric follows for Eaton drive repairs.

Take Notes

This is often a subject that is passed by many individuals who are attempting to troubleshoot industrial electrical equipment. Before Precision Electric begins to perform Eaton drivestroubleshooting, qualified technicians take note of many important aspects of the equipment including, but not limited to:

  • Eaton VFD Model Number
  • VFD Serial Number
  • Reason for Service
  • Urgency (Rush Overtime or Standard)
  • Visual Inspection of External Device

Diode and IGBT Tests

When Eaton drivesTroubleshooting exceeds parameter changes, Precision Electric tests the input and output power sections of the Eaton VFD. This step is essential prior to applying power to the VFD unit. If for any reason there is a short on the input side or output side of the VFD, further damage can be caused to the unit if power is applied to it.

For this reason, Precision Electric uses meters to properly test the input and output power sections of the Eaton VFD prior to applying power to the actual unit. If a short is found, the unit can be disassembled and the cause of the short can be diagnosed and quoted for repair. If the repair is too costly, then a replacement is offered to the customer.

Power Up

If the input and output power sections test healthy during this step of the Eaton drivestroubleshooting and repair process, Precision Electric will power up the unit and perform amp reading and output frequency tests. Precision Electric prefers to slowly increase power voltage to the unit until the rated input voltage of the VFD is achieved.

Depending on whether or not the VFD provides a display will determine what further action(s) will be taken. If display is unavailable, dis-assembly and diagnosis of the internal power supply of the control section of the VFD is likely necessary to further evaluate cause of failure and establish cost and lead time for the Eaton VFD repair.

Run A Motor

If the previous three tests have passed during the Eaton drives troubleshooting and repair process, then it is time to run a basic jog function of the VFD with a simple template program. Often when a VFD comes into our facility, we make sure to backup whatever program is currently stored in the VFD prior to inputting a template program and running a test procedure. This is to ensure we have a backup copy of the program.

The best method for backing up depends on the brand of drive, but after it has been backed up, we either reset the Eaton VFD to factory defaults through the keypad and recommission a basic start, stop and job application or closed loop if an encoder is involved. If the motor will not run, it will be necessary to check the output voltages and current ratings going to the motor to see if the VFD is functioning properly to rotate the motor.

Contact Customer

At this point we have determined the cause of failure, estimated lead time and cost of the Eaton drivestroubleshooting and VFD repair. If the VFD has tested good entirely, then further underlying issues are communicated with the customer. This is when Precision Electricwill gather application specific information from the customer to establish whether or not it may be some outside issue associated with the system including, but not limited to, PLC communications, faulty IO, bad wiring or even bad cabling. There is no single way to do this step, as it depends on a wide variety of variables.

Send Service Tech

If the customer cannot establish failure on any other aspect of the machine and the Eaton drivestroubleshooting tests appear to be good, then it may be necessary to send a Precision Electric field service technician on site to establish cause of failure. Precision Electricfield service technicians are trained to troubleshoot any issue ranging from standard VFD repair to advanced robotics, servo systems, electric motor issues and more. Precision Electric field technicians are trained to establish cause of failure and come up with solutions as quick as possible.

To learn more about Eaton Drives Troubleshooting or for Eaton VFD Repair Quotes, contactPrecision Electric, Inc.







Electric Motor Service Factor

What does the electric motor Service Factor really mean?

The nomenclature of service factor on an electric motor nameplate is designated by “S.F.”. Service factor is a multiplier, which when applied to the rated horsepower, gives the allowable horsepower loading the machine is capable of delivering without causing significant damage to the unit.

Electric motor service factor is not a direct multiplier to motor current but it is a good rule to follow since horsepower output is often proportional to current draw.For most motors, using the service factor multiplier on the nameplate to the full load current rating will provide an accurate assessment of allowable full load current.There are some exceptional cases in which this rule may not apply. Operating an older until with lower efficiency ratings or operating in conditions in which power factoris low will create less temperature increase per ampere than in modern ‘T’ frame motors will heat up dramatically when operated over full load nameplate current ratings.

The key to maximum allowable current draw is how the draw in excess of nameplate will affect core heating and the ability of the core to dissipate that heat. Electric motor service factor should never be engineered into an application. Electric motors should never be operated within their service factors for prolonged time periods. The electric motor service factor must be viewed as insurance against motor failure during periods of temporary load or power problems.

If your electric motors are operating within service factor range, find out why. Correct the problem or at the very least, know the problem. Motors designed to operate on 460 volt systems will draw slightly higher current when operated at 480 volts. Units that have been rewound many times may have sufficient core losses to account for slightly higher current draw. These factors considered should emphasize the need for a class H insulating system on all rewinds.

To learn more about electric motor service factor or for repair and replacement quotes, contact Precision Electric.

Motor Speed Controllers

There are three general types of motor speed controllers – AC motor speed controllers, DC Motor motor speed controllers, and Eddy Current motor speed controllers.Eachtype of motor speed controller can be divided into different variations. Each type of motor speed controller system will include an electric motor and aspeed control unit. Motor speed control technology today mainly consists of solid state electronic components in a single system. Older speed controlsystems use mechanical parts that, over time, result in failure due to moving and worn parts.

AC Motor Speed Controllers

AC motor speed controllers are also known as alternating current speed controllers, adjustable speed drives, variable frequency drives, VFD’s, inverters,and micro drives. AC motor speed controllers are used in many applications such as air compressors, conveyors, injection moulding, food processing, wastewater treatment pumps, HVAC fans and blowers, and other industrial applications. Approximately one third of the world’s electrical energy is supplied byelectric motors in fixed-speed centrifugal pump, fan, and air compressor applications. This proves that energy efficiency improvement can be implementedwhere electric motors are operating without speed AC motor speed controllers.

DC Motor Speed Controllers

DC Motor Speed Controllers are also known as DC variable frequency drives, or DC drive systems. The speed of a DC motor is directly proportional to armature voltage and inverselyproportional to motor flux; either armature voltage or field current can be used to control the motor speed. DC Motors have become expensive and todaymost dc motor speed control systems have been retrofitted by pairing an AC motor with an AC motor speed controller. AC motor speed controllers are moreenergy efficient, less expensive and more available than DC motor speed controllers.

Eddy Current Motor Speed Controllers

Eddy current motor speed controllers are a combination of a fixed speed motor and an eddy current clutch. The clutch contains a fixed speed rotor and anadjustable speed rotor separated by a small air gap. A direct current in a field coil produces a magnetic field that determines the torque transmittedfrom the input to the output rotor. The controller provides closed loop speed regulation by varying the clutch current, allowing the clutch to transmitenough torque to operate at the desired speed. Speed feedback is provided by an integral AC tachometer.

Eddy current controllers are less efficient than all other types of motorspeed controllers. Nearly all eddy current controllers are obsolete today.Somemanufacturers still use eddy current motor speed controllers, but when the equipment fails, it’s expensive to repair and oftenimpossible to replace. Eddy current motor speed controllers are upgraded via replacement by pairing an AC motor with an AC motor speed controller.

For motor speed controller replacement, repair, or retrofit quotes, Contact Precision Electric, Inc.