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When two oscillators or
vibrating assemblies are brought within close proximity of each other or
are connected by a common link, they have a tendency to try to
synchronize. The quicker synchronization occurs, the better. This is one
of the most misunderstood facts about Besser vibration.
If the speed of two vibrating
shaft assemblies are not equal, the higher speed vibrator will raise the
speed of the slower vibrator. The higher speed vibrator will then lag by a
certain phase angle. This loads down the higher speed vibrator causing the
motor current to go up while the motor current of the slower vibrator goes
down. The greater the differential in vibrator speeds – the greater the
lagging phase angle becomes until slipping occurs and/or production
problems arise.
To properly check the vibrator
speeds, disable or disconnect the right hand vibrator motor. Turn on the
left hand vibrator motor and with a digital style photo tachometer, or one
that can distinguish the difference of 1 or 2 rpm's, check and record the
speed of the left hand vibrator sheave. Turn off and disable the left hand
vibrator motor. Enable the right hand vibrator motor and do the same
checks on the right hand vibrator sheave and record the information.
Compare the two readings to
determine the differential. In today’s high production plants, where
every fraction of a second counts, the optimum rpm differential is 5 or
less. A higher differential may result in premature mold wear and lower
production rate cycles.
Recommendations:
- After changing molds, use a digital
amprobe and record the running amps of all three legs of both motors.
Compare the average readings on both motors. If the differential is
greater than 3 amps – check the sheaves.
- Recommended speed for posapac vibration is
2800 rpm's.
- The AFC SmartPac® frequency is adjustable
from 2500 – 3100 rpm’s even though shaft speeds in excess of 2900
rpm’s may result in premature vibrator shaft bearing failure.
- Never mix a U frame motor with a T frame
motor because they have different torque curves.
Hand Held Digital Tachometer
To assume that your
vibrator shafts are turning at the proper rpm is no longer an acceptable
practice. With the hand held digital tachometer, you
can quickly and accurately measure the rpm speed of your vibrator shafts.
Part Number 02-112910 - Hand
Held Digital Tachometer
Range: 6-30,000 RPM
Reading Distance: 1.9’ – 11.8’
Accuracy: ± 1 RPM
Battery Operated
Digital Stroboscope
Quickly and accurately measure
the rpm of the vibrator shafts.
Part Number 02-115212
Range: 100-8,000 RPM
Accuracy: ± 1 RPM
110 Volts AC only
Digital Amprobe Ammeter
Now available from Besser, to
assist with electrical troubleshooting,
is this digital Amprobe Ammeter. This
digital clamp-on, Volt / Ohm / Amp meter is simple
to use and is a rugged heavy-duty tool.
Part Number 02-112641 -
Amprobe Ammeter
SAFETY BULLETIN
This notice is issued to advise you that some previously accepted shop practices may not be keeping up with changing Federal and State Safety and Health Standards. Your current shop practices may not emphasize the need for proper precautions to insure safe operation and use of machines, tools, automatic loaders and allied equipment and/or warn against the use of certain solvents or other cleaning substances that are now considered unsafe or prohibited by law. Since many shop practices may not reflect current safety practice and procedures, particularly with regard to the safe operation of equipment, it is important that you review your practices to ensure compliance with Federal and State Safety and Health Standards.
IMPORTANT
The operation of any machine or power-operated device can be extremely hazardous unless proper safety precautions are strictly observed. Observe the following safety precautions:
Always be sure proper guarding is in place for all pinch, catch, shear, crush and nip points.
Always be sure that all personnel are clear of the equipment before starting it.
Always be sure the equipment is properly grounded.
Always turn the main electrical panel off and lock it out in accordance with published lockout/tagout procedures prior to making adjustments, repairs, and maintenance.
Always wear appropriate protective equipment such as safety glasses, safety shoes, hearing protection and hard hats.
Always keep chemical and flammable material away from electrical or operating equipment.
Always maintain a safe work area that is free from slipping and tripping hazards.
Always be sure appropriate safety devices are used when providing maintenance and repairs to all equipment.
Never exceed the rated capacity of a machine or tool.
Never modify machinery in any way without prior written approval of the Besser Engineering Department.
Never operate equipment unless proper maintenance has been regularly performed.
Never operate any equipment if unusual or excessive noise or vibration occurs.
Never operate any equipment while any part of the body is in the proximity of potentially hazardous areas.
Never use any toxic flammable substance as a solvent cleaner.
Never allow the operation or repair of equipment by untrained personnel.
Never climb or stand on equipment when it is in operation.
It is important that you review Federal and State Safety and Health Standards on a continual basis. All shop supervisors, maintenance personnel, machine operators, tool operators, and any other person involved in the setup, operation, maintenance, repair or adjustment of Besser-built equipment should read and understand this bulletin and Federal and State Safety and Health Standards on which this bulletin is based.
Posted 10 July 2000
Revised 6 July 2006
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