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Summary of Contents for OHAUS Defender D15HR
- Page 1 SERVICE MANUAL ™ Defender Bases: – Rectangular (H Series) – Square (Q Series) – Square Washdown (W series) Ohaus Corporation 19A Chapin Road, P.O. Box 2033, Pine Brook, NJ 07058-2033 (973) 377-9000...
- Page 3 – Square (Q Series) – Square Washdown (W series) The information contained in this manual is believed to be accurate at the time of publication, but Ohaus Corporation assumes no liability arising from the use or misuse of this material. Reproduction of this material is strictly prohibited.
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Page 5: Table Of Contents
Specifications for Defender Square Washdown Bases (Large) ......1-5 3-2. Overload Gap Settings For Defender H-Q-W Bases..........3-3 Load Cell Resistance Readings ................4-1 Load Cell Output Readings ...................4-3 Defender H-Q-W Bases: Housing & Internal Parts ..........5-3 (continued next page) Ohaus Corporation www.ohaus.com Defender™ H-Q-W Series Service Manual... - Page 6 Location of bottom Overload Stops ...............3-3 Resistance elements on H and Q series Bases ............4-1 Positions A, B, C and D are Centered..............4-4 Off Center Load adjustment points................4-5 Defender H-Q-W Bases: Housing & Internal Parts ..........5-2 Defender™ H-Q-W Series Service Manual Ohaus Corporation www.ohaus.com...
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Page 7: Chapter 1 Introduction
CHAPTER 1 INTRODUCTION INTRODUCTION This service manual contains the information needed for diagnosis and repair of Ohaus Defender Square, Rectangular, and Square Washdown Bases (the H-Q-W Series). The contents of this manual are contained in five chapters: Chapter 1 Introduction – Contains information regarding service facilities, tools and test equipment, test masses, specifications, service strategy, and the mechanical and electronic operation of the Base. -
Page 8: Tools And Test Equipment Required
Span calibration. SERVICE STRATEGY The Load Cells used in Ohaus Bases are non-repairable. The repair method for the Base is direct replacement of Load Cells with connecting cable and hardware. Each base contains the following basic replaceable assemblies: Platform, Load Cell with Connecting Cable, and Down Stop and mounting hardware. -
Page 9: Specifications
CHAPTER 1 INTRODUCTION SPECIFICATIONS Complete specifications for the Ohaus Defender H-Q-W Series Bases are listed in Tables 1-1, through 1-6. When a Base has been serviced, it must meet the specifications listed in the table. Before servicing the Base, determine what specifications are not met. -
Page 10: Specifications For Defender Square Bases (Regular)
14°F to 104°F / -10°C to 40°C Shift Tolerance new ±1d Shift Tolerance Maint. ±2d Base Dimensions 18 x 18 in. / 457 x 457 mm 24 x 24 in. / 61 x 61 cm Ohaus Corporation www.ohaus.com Defender™ H-Q-W Series Service Manual... -
Page 11: Specifications For Defender Square Washdown Bases (Regular)
14°F to 104°F / -10°C to 40°C Shift Tolerance new ±1d Shift Tolerance Maint. ±2d Base Dimensions 18 x 18 in. / 457 x 457 mm 24 x 24 in. / 61 x 61 cm Defender™ H-Q-W Series Service Manual Ohaus Corporation www.ohaus.com... -
Page 12: How Load Cells Operate
At zero load, all strain gauges are unstressed. Weight placed on the Platform bends the beam, causing two gauges to stretch and two to compress in opposition, changing the electrical resistance of the circuit. Ohaus Corporation www.ohaus.com Defender™ H-Q-W Series Service Manual... -
Page 13: Route Of Electrical Load Cell Input And Output
0.02mV per kg change in the load, that is, 10mV/500=0.02mV per kg. At a load of 250kg the signal voltage would thus increase by 5mV from the value measured at no load. Defender™ H-Q-W Series Service Manual Ohaus Corporation www.ohaus.com... - Page 14 CHAPTER 1 INTRODUCTION Ohaus Corporation www.ohaus.com Defender™ H-Q-W Series Service Manual...
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Page 15: Chapter 2 Troubleshooting
3. Perform an Output Voltage Test: Measure the no load, 50% load and full load output. The reading should meet the Load Cell specifications. (See Chapter 4.) The Load Cell output should be very close to linear over its capacity range. – Defender™ H-Q-W Series Service Manual Ohaus Corporation www.ohaus.com... - Page 16 CHAPTER 2 DIAGNOSTIC GUIDE Ohaus Corporation www.ohaus.com Defender™ H-Q-W Series Service Manual...
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Page 17: Chapter 3 Maintenance And Repair Procedures
CHAPTER 3 MAINTENANCE AND REPAIR PROCEDURES PREVENTIVE MAINTENANCE Ohaus bases should be carefully handled, stored in a clean, dry area, and cleaned periodically. Follow these precautionary steps: – When a base has had chemicals or liquids spilled on it, all exterior surfaces should be cleaned as soon as possible with warm water on a damp cloth. -
Page 18: Overload Stop Adjustments
2. Use the appropriate size feeler gauge in the Gap (see Table 3-1), and turn the set screws until a slight drag is felt on the feeler gauge. Jam Nut Set Screw Overload Stop Figure 3-3. Overload Gap Setting. Figure 3-4. Location of top Overload Stops. Ohaus Corporation www.ohaus.com Defender™ H-Q-W Series Service Manual... -
Page 19: Overload Gap Setting
1mm (0.4in.) D250QX 6mm (0.23in.) 1mm (0.4in.) D10WR 2mm (0.78in.) 0.8mm (0.31in.) D25WR 2mm (0.78in.) 0.8mm (0.31in.) D50WL 3mm (0.11in.) 1mm (0.04in.) D100WL 4mm (0.157in.) 1mm (0.04in.) D250WX 6mm (0.23in.) 1mm (0.04in.) Defender™ H-Q-W Series Service Manual Ohaus Corporation www.ohaus.com... - Page 20 CHAPTER 3 MAINTENANCE AND REPAIR PROCEDURES Ohaus Corporation www.ohaus.com Defender™ H-Q-W Series Service Manual...
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Page 21: Chapter 4 Testing
The following tests require a Digital Multimeter, an Indicator and hand tools. The Digital DC Voltmeter should have a reading range from 1 mV to 50 V full-scale. It should be capable of reading differences of one micro-volt per increment. The indicator can be either the Ohaus Defender 5000, or an equivalent commercial indicator. -
Page 22: Calibration With An External Indicator
1. Using a voltmeter, measure and record the excitation voltage supplied by the Indicator. Most Ohaus indicators supply 5 volts dc for the excitation voltage. 2. Using an mV meter, measure and record the signal voltage with no load on the base. -
Page 23: Load Cell Output Readings
Zero + 5.6 D50WR/50kg 1.7 ± 2.0 Zero + 2.4 Zero + 4.8 D100WL/100kg 1.3 ± 2.0 Zero + 2.7 Zero + 5.4 D250WX/250kg 0.34 ± 2.0 Zero + 2.5 Zero + 5 Defender™ H-Q-W Series Service Manual Ohaus Corporation www.ohaus.com... -
Page 24: Performance Tests
2. Check the variation between mass weights and indicator reading against specified Shift Tolerance in Table 1-1. Figure 4-2. Positions A, B, C and D are centered at each quarter of the base platform. Ohaus Corporation www.ohaus.com Defender™ H-Q-W Series Service Manual... -
Page 25: 4.5.2 Adjusting Off Center Load
Note: It is not recommended that you try to adjust more than –5 counts if the beam has been filed already. If the beam has not been filed previously, you can adjust –10 counts. Remember, when filing you are weakening the beam. File a little at a time. Defender™ H-Q-W Series Service Manual Ohaus Corporation www.ohaus.com... -
Page 26: 4.5.3 Full Load Test
Specification Tables 1-1 through 1-6. The Base must meet all specifications as listed. 2. If the Base fails the Full Load Test, check and set the Overload Stops. (See Section 3.3.) Ohaus Corporation www.ohaus.com Defender™ H-Q-W Series Service Manual... - Page 27 In all cases where a part is replaced, the base must be thoroughly checked after the replacement is made. The base MUST meet the parameters of all applicable specifications in this manual. If further technical information is needed, please contact your local Ohaus office or: Ohaus Corporation, www.ohaus.com 19A Chapin Road P.O.
- Page 28 CHAPTER 5 PARTS LISTS & DIAGRAMS DEFENDER RECTANGULAR (H) BASES: PARTS Figure 5-1. Defender Rectangular (H) Bases: Parts Ohaus Corporation www.ohaus.com Defender™ H-Q-W Series Service Manual...
- Page 29 Level Kit Leveling Feet When replacement parts are needed, refer to the spare part list for the model you are servicing. Parts lists are available from your local Ohaus office, or visit Ohaus.com. Defender™ H-Q-W Series Service Manual Ohaus Corporation www.ohaus.com...
- Page 30 CHAPTER 5 PARTS LISTS & DIAGRAMS DEFENDER SQUARE (Q & W) BASES: PARTS Figure 5-2. Defender Square (Q & W) Bases: Parts Ohaus Corporation www.ohaus.com Defender™ H-Q-W Series Service Manual...
- Page 31 Drawing Item Description Rubber Center Load Pad Rubber Corner Load Pad Overload Stop Jam Nuts and Set Screws Load Cell Mounting Bolt Load Cell Load Cell Mounting Washers Level Kit Leveling Feet Defender™ H-Q-W Series Service Manual Ohaus Corporation www.ohaus.com...
- Page 32 CHAPTER 5 PARTS LISTS & DIAGRAMS Ohaus Corporation www.ohaus.com Defender™ H-Q-W Series Service Manual...
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Page 33: Appendix A: Glossary
V output over full range, they will quote the milli-Volt output per volt of excitation, or in its short form, mv/V. Most Ohaus Indicators provide an excitation voltage of 5 Volts dc. - Page 34 APPENDIX A GLOSSARY Ohaus Corporation www.ohaus.com Defender™ H-Q-W Series Service Manual...
- Page 36 *80252596* P/N 80252596 SERVICE MANUAL: DEFENDER™ H-Q-W SERIES BASES...
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