Case histories from difficult balance jobs by troy d. With only a minor break in operation insitu balancing yields a. Single plane balancing is the placement of a weight in one plane to achieve an acceptable level of balance. With only a minor break in operation insitu balancing yields a well balanced. The following procedure is used in twoplane balancing. What is single plane balancing and how does it work. Pdf static and dynamic balancing of helicopter tail.
Unbalance is the most common cause of damage in rotating machines. So far, we have been dealing with a simple single plane balance. This technical article develops a universal computer program for the twoplane balance of rigid rotors, by means of a unified treatment of the system and the convention for the phase measurement, which. The two general types of dynamic balancing machines that have received the widest acceptance are the soft or flexible bearing machine and the hard or rigid bearing machine. Re and record the new vibration level the procedure for two plane bal. Balancing rigid rotors in the field reliable plant. Multiplane balance this includes a balance process where it is necessary to make balance corrections at 2 or more axial locations along the shaft where each plane will have normally different weights and phase angles. Balancing involves redistributing the mass which may be carried out by addition or removal of mass from various machine members balancing of rotating masses can be of 1.
A full accelerometer, phase sensor and daq box is needed for vibration readings. Poor balancing is one of the main causes for premature machine failure. The diagram below shows masses on two rotors in planes b and c. Re and record the new vibration level the procedure for twoplane bal. The technique, based upon influence coefficients, extends the singleplane four run balancing procedure to two planes. Methods are presented for determining suitable trial weights both amount and position to achieve the desired results. Unit 6 introduction to balancing introduction to balancing. Perform a check balance on the fully assembled rotor after the component assembly procedure above, with final corrections normally on two correction planes near the ends of the rotor near bearings a. In the following example a longish rotor is balanced in two planes. Benefits without disassembling the rotor insitu many machines can be balanced which significantly improved vibration levels. They are the amount and position of the two correction weights required to balance the rotor. This technical article develops a universal computer program for the two plane balance of rigid rotors, by means of a unified treatment of the system and the convention for the phase measurement, which can be used by any general balancing equipment.
These reference planes are usually placed near the support bearings. Balance corrections were computed by determining the difference between. Balancing of rotating masses 837 it may be noted that equation i represents the condition for static balance, but in order to achieve dynamic balance, equations ii or iii must also be satisfied. Field balancing is the process of correction mass in that plane only. Balancepro is a technical tool to assist the inshop single and twoplane high precision horizontal rotor balancing procedure. Practical approach to precision balancing 7 inplace two plane balancing of overhung rotors. Elevation view of a rotor having an imbalanced mass. The following procedure is used in two plane balancing. A rigid rotor can be balanced at the two end planes and will stay in balance when in service. Move the black line with the up or down buttons to single plane bal. The plane of the disturbing mass may lie on the left or right of the two planes containing the. Rotating machinery rotor balancing lifetime reliability. This balancing pro cess is often known as dynamic balancing because the unbalance. Both bearing reactions occur in the same plane but in opposite directions.
Single plane balancing 3 press firmly the onoff or escape or ok button until the instrument starts. Pdf static and dynamic balancing of helicopter tail rotor. When the rotor is completely balanced then on rotating it at different rpm, it will not undergo vibrations. Piedmont chapter vibration institute training symposium 10. One participant couldnt visualize how vibration on an overhung rotor fig. One of the factors is the ratio of the length of the rotor l to the diameter of the rotor d. Selecting one plane or two plane balancing is not straightforward. Balancing of a single rotating mass by a single mass rotating in the same plane. Dual plane is used, when the rotor shaft is long balance both sides or. The technique, based upon influence coefficients, extends the singleplane fourrun balancing procedure to two planes. Static and dynamic balancing of helicopter tail rotor blade using two plane balancing method balancing is a rotating component is critical in any mechanism. Rotor balancing procedures can generally be divided. Balancing in one plane if the system is a simple disc then. A flexible rotor will require multiplane balancing.
The basics of balancing 202 balance technology inc. The other factor is the operating speed of the rotor. Balancing may be performed on the planes of unbalances or any other two convenient planes. The plane of the disturbing mass may be in between the planes of the two balancing masses, and 2. Move the black line with the up or down buttons to measurements and press the ok button. An equal mass, placed source of vibration in machines with by adding compensating masses to the at an angle of 180 to the unbalanced rotating parts. Using two probes in the x and y directions, a relationship can be plotted with xy superimposed or plotted verse each other.
Balancing of a single rotating mass by two masses rotating in different planes. Fist volume 22, field balancing large rotating machinery. General computer program for two plane balancing of rigid rotors. Dynamic unbalance is also referred to as two plane unbalance, indicating. Remain skeptical during the balancing process and use the balancing procedure as a diagnostic tool.
A balancing report will appear on the right side of the window. If a rotor is balanced on a low speed balancing machine. Static and dynamic balancing of helicopter tail rotor blade using twoplane balancing method article pdf available in jurnal teknologi 7122. On overhung narrow rotors, it becomes more difficult to separate the influence of the two weight planes on the two measurement planes. Proximity probe on a magnetic mount, above turbine guide. It provide single and twoplane dynamic balancing services for fans, grinding wheels, spindles, crushers, pumps and other rotating machinery. There are four variables to be dealt with when balancing any rigid rotor. The following two possibilities may arise while attaching the two balancing masses. This is appropriate for components such as individual compressor or turbine discs. This paper presents, and experimentally verifies, a twoplane balancing technique for rigid rotors and possibly flexible rotors operating at a constant speed.
It can be found in fans, ventilators, belt pulleys and couplings. Standard balancing procedure equations are used in calculations. Performing a procedure like this in two planes becomes an iterative process in determining the influence coefficients. This measurement is not needed for balancing the rotor, but will be used later as a check on calculations. Vibration vector vibration amplitudes for the balancing is documented as amplitude and phase. This occurs when there is no resulting turning moment along the axis. Single plane unbalance can be pictured by imagining a disc shaped part, such as a bicycle wheel, with a weight taped to the rim. Dynamic balancing of rotating machinery experiment technical. Jackson 1991 showed how to perform singleplane balancing by plotting vibration readings amplitude and phase as vectors on polar graph paper. A procedure by which the mass distribution of a rigid rotor is resolved into two planes and adjustments made by adding or removing mass in those planes in order to reduce the primary force and. In addition, sometimes narrow overhung rotors dont respond well to twoplane balancing. This paper proposes a new single plane balancing method capable with one shot running. Balancing is the process of aligning a principal inertia axis with the geometric axis of. So far, we have been dealing with a simple singleplane balance.
New vector plot 3 on chart shows fan balanced to 10 times below original 5 mils at start of balancing procedure. Two plane balancing machines, or dynamic balancing machines, are used for correcting static and dynamic unbalance. The nplane is based on the concepts of the modal technique. Vertical balancing machines and for horizontal enddrive machines. The sensor should be mounted at a distance of 18 3mm to metal surface serving as. The two main methods of measuring and correcting unbalance are single plane static balancing and twoplane dynamic balancing. With single plane, the unbalance is only in one plane, i. If a rotor is balanced on a low speed balancing machine assuming it is rigid and then in service becomes flexible, then unbalance and thus high vibration, will be the result. For many years, balancing has been performed using graphical techniques as shown in figure 8. Balancing procedure an overview sciencedirect topics.
Balancers from pruftechnik are optimized for detecting and. This occurs when there is no resultant centrifugal force and the centre of gravity is on the axis of rotation. Vibxpert ii balancer field balancing in one plane or two planes. The balancing procedure can be fftbased or based on order tracking for the most accurate results. These two additional planes are for the twobearing system and are necessary in this school of balancing. Advanced field balancing concepts kelm engineering.
These two additional planes are for the two bearing system and are necessary in this school of balancing. Balancing machines types, classification, and methods. Application notes static and dynamic balancing of rigid rotors. Static and dynamic balancing of helicopter tail rotor. Static and dynamic balancing of helicopter tail rotor blade using twoplane balancing method balancing is a rotating component is critical in any mechanism. Single plane balancing is the placement of a weight in one plane to achieve an acceptable level of balance all balancing that is done without spinning the component up to operating speed is said to be single plane balancing. Details of the software products used to create this pdf file can be found in the. The basic steps for single plane balancing by pruftechnik. Singleplane balancing is relatively easy, but requires a minimum of three four runs if a trim balance is needed. Each correction weight is located in one of the arbitrary chosen radial reference planes on the rotor. For field balancing, stop the machine to attach a reflecting tape on the rotating shaft to. The phase angle of the heav y spot is clearl y defined from the timing mark on the disk. Plan view of an imbalanced rotor at the upper guide bearing. Determine the masses to be added on the rotors in planes a and d at radius 40 mm which will produce static and dynamic balance.
All balancing that is done without spinning the component up to operating speed is said to be single plane balancing. Now you can send the contents of the balancing report to the xtrend machine database. When the plane of the disturbing mass lies on one end of the planes of the balancing. As a general rule of thumb, we can refer to the table shown below. To balance the rotor using 2 plane balancing a crosscheck. The vibxpert ii balancer is a rugged yet lightweight device for field balancing of rotating machinery in one plane or two planes. If balance attempt is not working as anticipated stop and think about what. Finally correction masses and the angles for two planes are calculated table 1. First, we perform an initial run with two simultaneous unbalance readings one in each plane. A balance program developed for the lead phase measuring system was used for searching the effective twoplane balancing solution for the lag phase system of measurement for an overhung rigid rotor. A procedure by which the mass distribution of a rigid rotor is resolved into two planes and adjustments made by adding or removing mass in those planes in order to reduce the primary force.
Dual plane is used, when the rotor shaft is long balance both sides or when also torque needs to be eliminated. Singleplane balancing is relatively easy, but expensive component damage, personal injury or death may occur if inexperienced personnel attempt to balance a component. Twoplane balancing of a rotor system without phase response. This is simply because narrow rotor weight planes are. Ralph buscarello developed this method of balancing when conducting balancing training. A procedure by which the mass distribution of a rigid rotor is resolved into two planes and adjustments made by adding or. When the bike is lifted off the ground, the wheel rotates and comes to rest with the weight at the bottom. Devoid of proper balancing, any vehicle be it in air, land or sea, it will affect stability, control and safety. Static and dynamic balancing of helicopter tail rotor blade. Apr 18, 2011 selecting one plane or two plane balancing is not straightforward.
Vibxpert ii balancer field balancing in one plane or two. Twoplane balancing of a rotor system without phase. Fundamentals for successful field balancing reliabilityweb. There are two types of unbalance, single and two plane. These results compare favorably with the results obtained using programmable calculator bruel and kjaer, 1989. The conditions 1 and 2 together give dynamic balancing. Imbalance is one of the most common causes of increased levels of vibration in plant equipment. The n plane is based on the concepts of the modal technique. Check balance process will normally allow limited balance correction, since major corrections would have been completed during assembly b. After balancing, no bearing reactions remain theoretically.