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Torque Transducers
TM Series
Torque Transducers
 
 
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SpecificationsPrinciplesApplicationsData SheetsManuals
Features
  • Integrated Torque and Speed Conditioning
  • Torque Range: 0.1 N·m to 10,000 N·m
    (0.07 lb·ft to 7375 lb·ft)
  • Accuracy: < 0.1%
  • Overload Capacity: 200%
  • Overload Limit: up to 400%
  • High Speed Applications: up to 50,000 rpm
  • Non-Contact (no slip rings)
  • No Electronic Components in Rotation
  • No Electrical Noise
  • Single DC Power Supply: 20 to 32 VDC
  • Immediate Speed Detection
  • Adjustable Torque Signal Frequency Limitation
  • Built-in Test Function
  • Stainless Steel Shaft
  • EMC Susceptibility Conforms to European Standards
  • Calibrated to METAS standards

Specifications
For complete technical specifications and detailed dimension drawings,
download the applicable data sheet (links at bottom of page).
Calculators
Series
Model
Number
Nominal
Rated Torque
TMB Series TM Series TMHS Series Shaft Ends View Drawing
Accuracy
Class
Maximum
Speed
(rpm)*
Accuracy
Class
Maximum
Speed
(rpm)*
Accuracy
Class
Maximum
Speed
(rpm)*
N·m lb·ft Smooth Splined PDF STEP**
TM TMB TM TMB
301 0.1 0.07 N/A 0.2% 20,000 N/A X    
302 0.2 0.15 N/A < 0.1% 20,000 N/A X    
303 0.5 0.37 < 0.1% 6000 < 0.1% 20,000 < 0.1% 40,000 X    
304 1 0.7 < 0.1% 6000 < 0.1% 20,000 < 0.1% 50,000 X  
305 2 1.5 < 0.1% 6000 < 0.1% 20,000 < 0.1% 50,000 X  
306 5 3.7 < 0.1% 6000 < 0.1% 20,000 < 0.1% 50,000 X  
307 10 7.4 < 0.1% 6000 < 0.1% 20,000 < 0.1% 50,000 X  
308 20 15 < 0.1% 6000 < 0.1% 20,000 < 0.1% 50,000 X  
309 20 15 < 0.1% 4000 < 0.1% 10,000 < 0.1% 32,000 X    
310 50 37 < 0.1% 4000 < 0.1% 10,000 < 0.1% 32,000 X    
311 100 74 < 0.1% 4000 < 0.1% 10,000 < 0.1% 32,000 X    
312 200 148 < 0.1% 4000 < 0.1% 10,000 < 0.1% 24,000 X X  
313 500 369 < 0.1% 4000 < 0.1% 10,000 < 0.1% 24,000 X X  
314 1000 738 TMB Not Available < 0.1% 7000 < 0.1% 16,000 X X    
315 2000 1475 TMB Not Available < 0.1% 7000 < 0.1% 16,000 X X    
316 5000 3687 TMB Not Available < 0.1% 5000 < 0.1% 12,000   X    
317 10,000 7375 TMB Not Available < 0.15% 5000 < 0.15% 12,000   X    
* For low speed testing (e.g. gear motors), consult Magtrol.
**Other CAD models available upon request.
 
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Operating Principles
Simple and reliable, the torque meter measuring system is based on the principle of a variable, torque-proportional transformer coupling. The principle has been adapted by Magtrol for the measurement of torque. The measuring system consists of two concentric cylinders, shrunk on the shaft on each side of the shaft's deformation zone, and two concentric coils attached to the housing.
Torque Transducer Operation Principle
 
Both cylinders have a circularly disposed coinciding row of slots and rotate with the shaft inside the coils. A constant alternating current with the frequency of 20 kHz flows through the primary coil. When torque is applied, the slots on the two cylinders do not overlap. Instead, the deformation zone undergoes an angular deformation and the slots begin to overlap. Thus, a torque-proportional EMF is induced in the secondary coil.

The conditioning electronics convert the EMF into a voltage between +10 and -10 V, depending on the direction of the torque. Speed measurement is integrated by means of an inductive proximity transducer trained on a toothed path cut directly into the outer cylinder.
 
Inside View of TM Torque Transducer
torque transducer cross section
 
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Applications
Magtrol torque meters provide dynamic torque and speed measurement of:
  • Propellers - aerospace, marine and helicopter
  • Windshield wipers, electrical windows, starters, generators and brakes in automobile industry
  • Pumps - water and oil
  • Reduction gears and gearboxes
  • Clutches
  • Motorized valves
  • Drills, pneumatic tools and other machine tools
  • Tachometers
 

Torque Limiter Testing on Drills

Drilling Machine Drilling Machine
A Model TM 311 Torque Transducer is used in the design along with a disc brake, coupling, swivel and universal joint for accuracy and reliability. BRP 125 Test Bench specially designed for testing torque limiter on a wide range of drills from 5 Nm to 200 Nm.
 

A large manufacturer of hand drills was in need of a test bench for testing the torque limiters of their drills. The aim of the test bench was to equip their repair shops with a versatile, easy and fast system capable of testing a wide range of repaired drills. The ideal test bench would be a stable setup with a maximum surface area of 800 × 800 mm, capable of measuring speed of rotation and maximum trip torque for a 5-200 Nm range of drills. The test cycle would include machine assembly, rotation at nominal speed and braking the machine until the torque limiter trips within a total test time of 3 minutes maximum per drill.

Magtrol SA was able to meet these expectations with the development of the BRP 125 Test Bench, using their TM 311 Torque Transducer along with a disc brake, coupling, swivel and universal joint. The drill is placed on the test bench and connected to the system with a quick male/female coupling, held by hand by the operator. A stop bar prevents the machine from turning on. The torque is transmitted by means of a Cardan (universal joint) and a swivel joint. The role of transmission by Cardan and swivel joint is to allow the test without having to align and fix the machine. Once the maximum speed is reached, the drill is braked by means of the disc brake controlled by an electropneumatic control.

The system is controlled by software that allows the user to save the test parameters and print out a test certificate for each drill tested. The certificate contains information on the type of drill, serial number, nominal speed, nominal torque, name of tester, date of the test and the test values, which are also output in a torque/speed diagram.

Since the TM 311 Torque Transducer is particularly suited to measurements of great accuracy in fairly large ranges, the BRP 125 Test Bench has been a success with great reliability, good mechanical stability and an excellent reproducibility (0.5%). The users are very satisfied with the performance and functionality of the bench.

 
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Magtrol, Inc (USA): 716-668-5555 • magtrol@magtrol.com ~ Magtrol SA (Switzerland): 41 (0)26 407 3000 • magtrol@magtrol.ch
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