MANUAL NO E1.2 Published in Dec.2004 Revised in Aug LF Series Linear Variable Differential Transformer INSTRUCTION MANUAL

Transcription

1 MANUAL NO E1.2 Published in Dec.2004 Revised in Aug LF Series Linear Variable Differential Transformer INSTRUCTION MANUAL

2 LF SERIES FOREWORD For safe operation... Thank you for using our LS Series Linear Variable Differential Transformer (LVDT). SHINKAWA Sensor Technology applies strict quality control and inspections to ensure the high reliability of its products. This instruction manual contains descriptive information, specifications, and operating setting, and adjusting procedures. Please study the contents of this manual and related manuals thoroughly before installing or operating the equipment, and keep it handy for future reference. "Safety Conventions" Please thoroughly study the following section entitled "Safety conventions" before operating the equipment. The safety symbols explained in this section are placed outside the left margin next to the text to which they apply. This unit is designed for use by specialists or persons thoroughly familiar with the field. Make sure that the end user receives the Instruction Manual delivered with this unit. Before use... When the unit is received, inspect it for damage suffered in transport and check whether it is the item you ordered. In the unlikely event that it was damaged in transport or does not function according to specifications, please contact the SHINKAWA Electric Office or dealer nearest you. Store the unit under the ambient conditions given in the specification. Avoid places where it is exposed to high humidity or corrosive gases. Disuse... Please contact a nearly service station when disposal. i

3 LF SERIES SAFETY CONVENTIONS Make it a rule to follow the instructions given in this manual. This manual contains important information designed to prevent personal injury and property damage, and ensure safe operation of the equipment. Familiarize yourself with the signs and symbols explained below before proceeding to read the manual, and observe the instructions given. Explanation of signs Symbols WARNING CAUTION Explanation Indicates a potentially hazardous situation which, if not avoided, could result in death or serious injury. Indicates a potentially hazardous situation which, if not a avoided, may result in minor or moderate injury. It may also be used to permit for property-damage-only accidents. * Serious injury refers to such injuries as loss of eyesight, injuries, burns (due to heat or cold), electric shock, fractures, and poisoning, that have permanent aftereffect and require hospitalization or long-term outpatient treatment. * Moderate or minor injury refers to such injuries as burns and electric shock that do not require hospitalization or long-term outpatient treatment. Property-damage-only accidents refers to consequential damage related to destruction of property and damage to the equipment. Explanation of symbols Symbols Explanation Indicates a prohibited action. Details are given in the text next to the symbol. Indicates a mandatory action. Details are given in the text next to the symbol. ii

4 LF SERIES CAUTION FOR SAFETY In order to operate this product safely, observe the contents of the caution described in this instruction manual. Shinkawa will not bear the responsibility for any damage caused by their violations. In order to operate the differential transformer safely! CAUTION MODIFICATION PROHIBTION MANDATORY Do not modify the differential transformer without permission. If modified, no product can be warranted. Before conducting the megger test (insulation test) of signal transmission cables, always disconnect the cables from the differential transformer and combined converter. In addition, after the test, first discharge charged electrons and then connect these cables to the respective devices. If connected with electrons charged, an instrument connecting the LVDT may be damaged. Be fully careful of handling the outer pipe and mounting blocks as they easily slide. Otherwise, fingers may get jammed in them or an injury may result during their handling. In addition, instrument damage or injury may result due to their slipping out. Always fix the transformer to the field fixture only using the outer pipe. If fixed using the core & extension rod, deformation or breakage may result. In addition, after being fixed, take the necessary measures for locking them. Do not apply any movement of causing eccentricity to the differential transformer when used. If applied, the deformation of the outer pipe or the deformation or damage of the core & extension rod may result. Do not replace the core & extension rod. Use the differential transformer body and its core & extension rod with the same manufacturer s serial numbers. If used in a different combination, the characteristics may worsen. Do not use the differential transformer as a footing. This transformer may sometimes be installed at places where used as a footing at the power generation plant site, etc. However never use it as a footing as this may cause its damage. If there is a fear of being used as a footing, close it with a cover for its protection. Installing environment Use the transformer within the operating temperature range described in the specification. If not, it may be damaged. iii

5 LF SERIES TABLE OF CONTENTS 1. OVERVIEW 1 2. STANDARDS REPLACEMENT OF PARTS 6-7 iv

6 1. OVERVIEW LF SERIES 1-1 OVERVIEW The LF Series linear variable differential transformer (LVDT) is a compound wound differential transformer designed by putting much emphasis on reliability and also so as to be most suitable for valve opening measurement. 1-2 OPERATING PRINCIPLE The LF Series linear variable differential transformer (LVDT), as shown in Fig. 1, is a compound wound differential transformer consisting of the primary and secondary coils and an iron core which moves between them. In Fig. 1, it is so designed that the iron core moves between the coils with the movement of an extension rod. Thus, if the constant energizing current (8 V rms, 1 khz and sine wave) is applied to the primary coil, as shown in Fig. 2(a), the relationship of V CD < V EF is established between the voltage V CD (between C and D) and the voltage V EF (between E and F) across the secondary coils. Similarly in Fig. 2(b), the relationship of V CD = V EF and in Fig. 2(c), that of V CD > V EF are established. As they change in proportion to the amount of iron core movement, as shown in Fig. 2(d), the voltage in proportion to the amount of iron core movement can be output through a detection circuit by finding the difference between V CD and V EF 8Vrms 1kHz A Primary coil B Extnsion rod Iron core Secondary coils C D E F Detection circuit(needs to be prepared by the user.) Output V EF +V Fig1. Diagram of showing construction V CD V CD <V EF V CD =V EF V CD >V EF 0% 0V Null point 100% V CD - V EF -V V CD V EF V CD V EF V CD V EF (a) 0% (b) 50%(Null)point (c) 100% (d) Output characteristics Fig 2. Diagrams of showing operating principle -1-

7 2. STANDARDS LF SERIES 2-1 SPECIFICATION Model Code LF- - A U Model Code Shape of outer pipe Stroke 100mm 250mm 300mm 400mm A Without collar L2(Outer pipe) 488mm 902mm 488mm 539mm 565mm 610mm L3(NULL) 593mm 1006mm 686mm 737mm 787mm 883mm Sensitivity 13.0mV DC/Vrms/mm 5.20mV DC/Vrms/mm 4.33mV DC/Vrms/mm 3.25mV DC/Vrms/mm Sensitivity error ±5% LF- - B U Model Code Shape of outer pipe Stroke 100mm 250mm 300mm 400mm B With collar L2(Outer pipe) 503mm 917mm 503mm 554mm 580mm 625mm L3(NULL) 608mm 1021mm 701mm 752mm 802mm 898mm Sensitivity 13.0mV DC/Vrms/mm 5.20mV DC/Vrms/mm 4.33mV DC/Vrms/mm 3.25mV DC/Vrms/mm Sensitivity error ±5% L2,L3 : Refer to Outline Drawing SPECIFICATIONS Stroke Excitation Operating temperature Linearity Input impedance Output impedance Temperature drift Insulation resistance Dielectric strength 100, 250, 300, 400mm 8Vrms, 1kHz, sinusoidal wave -20 to +150 C Within ±1.0% of F.S. More than 300Ω, 1kHz (at Null point) Less than 250Ω (one side), 1kHz (at Null point) Within ±0.02% of F.S./ C More than 100MΩ at 500VDC (between each lead wire and body, between primary coil and secondary coil) 3mA or less at 1500VAC 60Hz for one minute (between each lead wire and body) Shock vibration 98m/s 2 (10g REF.) at 150Hz Lead wire 0.2mm 2 Connected equipment VM-21D or refer to following diagram.(prepared by customer) : Prepared by customer Excitation A Primary coil B LVDT Secondary coil C D E F Output Lead color A: Brown B: Yellow C: Red D: Blue E: Green F: Black CONNECTION DIAGRAM Detection circuit E1.4

8 2. STANDARDS LF SERIES 2-2 OUTLINE DRAWING LF- - AU Model code Stroke 100mm 250mm 300mm 400mm L L L Dimensions : mm 7 Lead wire 6 Mounting block 2 5 Body 4 Mounting block 1 3 Outer pipe 2 Jam nut 1 Core & Extension rod No. NAME -3-

9 2. STANDARDS LF SERIES LF- - BU Model code Stroke 100mm 250mm 300mm 400mm L L L Dimensions : mm 7 Lead wire 6 Mounting block 2 5 Body 4 Mounting block 1 3 Outer pipe 2 Jam nut 1 Core & Extension rod No. NAME -4-

10 2. STANDARDS LF SERIES 2-3 NAME OF EACH SECTION AND DESCRIPTION 1 Core & extension rod (hereafter called the rod ) Output voltage changes as the rod moves between the coils together with the movement of the outer pipe ( 3 ). Note: The LVDT is fixed to the machine only using the outer pipe ( 3 ). Therefore never fix them using the rod end thread (1/4-28UNF). Machine side 1/4-28UNF Outer pipe Rod Jam nut 2 Jam nut Used to fix the rod to the outer pipe. Note: Do not loosen this jam nut. If so, the position of the rod ( 1 ) changes. 3 Outer pipe The LVDT is fixed to the machine using the outer pipe. As the rod ( 1 ) and the jam nut ( 2 ) are fixed to the outer pipe, the rod moves with the movement of the outer pipe fixed to the machine. Machine side 4 Mounting block 1 This block is fixed to the machine. In addition, it is not fixed to the outer pipe ( 3 ). 5 Body There are coils inside the body which is fixed to the mounting block 2( 6 ). 6 Mounting block 2 This block is fixed to the machine. 7 Lead wires Six lead wires with an area of 0.2 mm 2 each are extended. They are covered with a protective tube. -5-

11 3. REPLACEMENT OF PARTS LF SERIES REPLACEMENT OF PARTS Each bearing used for the LVDT differs depending on the operating condition. However, it is recommended that it be replaced with a new one after checking its rotating condition during periodic inspection from the standpoint of preventive maintenance. Note: Conduct its replacement at places where solids do not fall onto it, nor tread foot passengers on it. For this replacement work, hot air (at a temperature of about 200 C) is required. 1 Separate the fixed block of the outer pipe from the machine. Machine side 2 Remove all of the bolts fixing the mounting block 1. 3 Pull the outer pipe out of the mounting block 1 and body. Rod Outer pipe Mounting block 1 Body Note: At this time, the pipe gets out of place together with the outer pipe. After that, do not bend nor scratch the pipe. 4 Pull the mounting block 1 out of the body and then remove all of the bolts fixing the mounting block 2. Mounting Mounting block 2 block 1 Body Wipe away dust attached to the body and mounting blocks with waste 5 Remove each bearing from the respective parts. Bearing 1 Bearing 2 Bearing 3 Rod Through hole Mounting block 1 Outer pipe Body Remove the bearing 2 while pushing it in the inward direction with a rod inserted through the through hole. At this time, do not bend nor scratch the pipe. As the bearing 3 is an elastic tube, cut it away with a cutter knife. -6-

12 3. REPLACEMENT OF PARTS LF SERIES 6 Replace all of these bearings 1 to 3 with new ones, respectively. (They are all made of Fluoro resin.) For each of the bearings 1 to 2, push it into the respective groove. For the bearing 3, first pass the elastic tube through the body until aligned with the groove and then contract it using the hot air. At this time, be fully careful that the elastic tube does not protrude from the groove nor is wrinkled. It is not necessary to apply lubricant to each bearing. Hot air (At about 200 C and for 15 to 20 sec) 7 Pass the mounting block 1 through the outer pipe. Counterbored hole At this time, be careful of the direction of the counterbored hole in the mounting block 1. 8 Pass the outer pipe through the body. Rod Outer pipe Bearing 2 Rod Bearing 3 Body Notes: When inserting the rod into the body, do not bend nor scratch it. Do not forcibly insert the bearings 2 to 3. 9 Fix each mounting block to the specified position. 10 Fix the outer pipe to the machine. Machine side 11 Finished -7-

13 Hiroshima Factory 4-22 Yoshikawa-kogyodanchi, Higashi-hiroshima , Japan Tel Fax [Field support & Repair Dept] service@sst.shinkawa.co.jp