Eddy-Current Dynamometers (WB Series)

Eddy-Current Dynamometer

Product Description

Eddy-Current Brake Dynamometers (WB Series) are ideal for applications requiring high speeds and also when operating in the middle to high power range. Eddy-Current Brakes provide increasing torque as the speed increases, reaching peak torque at rated speed. The dynamometers have low inertia as a result of small rotor diameter. Brake cooling is provided by a water circulation system, which passes inside the stator to dissipate heat generated by the braking power. The water cooling in the WB provides high continuous power ratings (max. 140 kW). The WB dynamometers have accuracy ratings of ± 0.3% to 0.5% full scale (± 2% for WB 2.7), depending on size and system configuration. Additional options include: high-speed version, speed pickup, mechanical rotor blocking device, OEM version IS and vertical mounting.


Model Rated Torque (Metric) Rated Torque (English) Rated Speed (rpm) Rated Power (kW) Maximum Speed - Standard Version (rpm) Maximum Speed - High-Speed Version (rpm) Downloads
1 WB 23 0.08 N·m 11.24 oz·in 20,000 0.30 100,000 100,000 step
1 WB 27 0.15 N·m 21.24 oz·in 20,000 0.30 100,000 100,000 N/A
2 WB 2.7-8K 0.30 N·m 42 oz·in 15,915 0.50 50,000 N/A step
3 WB 2.7-8K 0.45 N·m 63 oz·in 15,915 0.75 50,000 N/A step
4 WB 2.7-8K 0.60 N·m 84 oz·in 15,915 1.00 50,000 N/A step
1 WB 43 1.50 N·m 13 lb·in 9550 1.5 50,000 65,000 S pdf | HS pdf |
IS pdf | MB pdf | step
2 WB 43 3 N·m 26 lb·in 9550 3 50,000 65,000 S pdf | HS pdf |
IS pdf | MB pdf | step
1 WB 65 10 N·m 88 lb·in 5730 6 30,000 50,000 S pdf | HS pdf |
IS pdf | MB pdf | step
2 WB 65 20 N·m 177 lb·in 5730 12 30,000 50,000 S pdf | HS pdf |
IS pdf | MB pdf | step
1 WB 115 50 N·m 36 lb·ft 2865 15 18,000 22,000 step
2 WB 115 100 N·m 73 lb·ft 2865 30 18,000 22,000 step
1 WB 15 140 N·m 103 lb·ft 2390 35 7500 N/A MB pdf | step
2 WB 15 280 N·m 206 lb·ft 2390 70 7500 N/A step
3 WB 15 420 N·m 309 lb·ft 2390 105 7500 N/A step
4 WB 15 560 N·m 413 lb·ft 2390 140 7500 N/A step

Key to PDF Drawing Abbreviations

Code Dynamometer Option
S Standard Dynamometer
HS High Speed (WB Series only)
IS Industrial Version
MB Mechanical Rotor Blocking Device (WB Series only)
DG Speed pickup (PB Series only)

Dynamometer Measuring Range


  • Motors:
    • Combustion engine (automotive, motorcycle, chainsaw, etc.)
    • Hybrid
    • Electric
    • Hydraulic (Aerospace, machinery)
  • Pumps (hydraulic, oil)
  • Propeller (Aerospace, marine, helicopter)
  • Automobile industry, torque measurement on labor and/or production (Formula 1, screen wiper, electrical windows, starter, generator, brake)
  • Reduction gear, gearboxes
  • Clutch, overload clutch
  • Motorized valve drill, pneumatic tools
  • Other machine tools

Model 1WB65 Dynamometer Testing Chainsaw

High acceleration of two stroke engine measurement with special coupling to decrease vibrations.

Model 2PB65-G Dynamometer Testing Starter for Combustion Engine

The dynamometer simulates the car engine for the starter test. The bell is used for measuring the torque coming from the initial rotation of the starter, limiting the inertia of the dynamometer.

System Options

To help you select the components for your motor testing system, this table shows which (currently available) electronics and software support Magtrol’s different types of dynamometers.

Model Description Hysteresis Dynamometers (including ED Series) Eddy-current Dynamometers Powder Brake Dynamometers Dial Weight Dynamometers
DSP7000 High-Speed Programmable Dynamometer Controller
6200 Dynamometer Controller/Readout
TSC 401 Torque/Speed Conditioner
5500 Dynamometer Switch Box
5501 Dynamometer Switch Box
M-TEST 7 Motor Testing Software
DES 410/411 Power Supply
5241 Power Amplifier Required for HD-825 Only
5200 Power Supply
5210 Current-Regulated Power Supply
5250 Current-Regulated Power Supply
TAB Dynamometer Tables
AMF Adjustable Motor Fixtures
FMF Fixed Motor Fixtures
PT T-Slot Base Plate
FRS Free-Run Speed Sensor
SBB 14 Signal Breakout Box

Tandem Dynamometers

Magtrol offers Eddy-Current and Powder Dynamometers mounted in tandem. In tandem, the unique features of each type of dynamometer brake are utilized, allowing the unit under test to be applied with nominal braking torque from zero speed to maximum rotation. The Tandem Dynamometers are available on a number of PB/WB combinations.

1 PB 43 + 2 WB 43 mounted in tandem with 3/4 hp single-phase motor and coupling



Model Download
WB/PB 43 Series pdf
WB/PB 65 Series pdf
1–2 WB 65 + K + 1–2 PB 65 pdf
2 WB 65 + MK + 2 WB 65 pdf
WB/PB 115 Series pdf
2 WB 115 + K + 2 WB 115 pdf
WB/PB 15 Series pdf

Dynamometer Selection

Magtrol Dynamometers cover a wide range of Torque, Speed and Mechanical Power ratings. To select the appropriate size Dynamometer for your motor testing needs, you will need to determine the Maximum Torque, Speed and Power applied to the Dynamometer:

Maximum Torque

It is important to consider all torque points that are to be tested, not only rated torque, but also Locked Rotor and Breakdown Torque. Dynamometer selection should initially be based on the maximum torque requirement, subject to determining the maximum power requirements.

Maximum Speed

This rating is to be considered independent of torque and power requirements, and is the maximum speed at which the Dynamometer can be safely run under free run or lightly loaded conditions. It is not to be considered as the maximum speed at which full braking torque can be applied.

Maximum Power Ratings

These ratings represent the maximum capability of the Dynamometer Braking System to absorb and dissipate heat generated when applying a braking load to the motor under test. The power absorbed and the heat generated by the Dynamometer is a function of the Torque (T) applied to the motor under test, and the resulting speed (n) of the motor. This is expressed in these power (P) formulas:

SI: P (watts) = T (N·m) x n (rpm) x (1.047 × 10-1)
English: P (watts) = T (lb·in) x n (rpm) x (1.183 × 10-2)
Metric: P (watts) = T (kg·cm) x n (rpm) x (1.027 × 10-2)
All of Magtrol's controllers, readouts and software calculate horsepower
as defined by 1 hp = 550 lb·ft / s. Using this definition:
hp = P (watts) / 745.7
To calculate power, use Magtrol's online motor power calculator

The Dynamometer’s ability to dissipate heat is a function of how long a load will be applied. For this reason, the Maximum Power ratings given are based on continuous operation under load, as well as a maximum of 5 minutes under load.

To safely dissipate heat and avoid Dynamometer failure, the maximum power rating
is the most important consideration in selecting a Dynamometer.