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.


ModelRated 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 230.08 N·m11.24 oz·in20,0000.30100,000100,000step
1 WB 270.15 N·m21.24 oz·in20,0000.30100,000100,000N/A
2 WB 2.7-8K0.30 N·m42 oz·in15,9150.5050,000N/Astep
3 WB 2.7-8K0.45 N·m63 oz·in15,9150.7550,000N/Astep
4 WB 2.7-8K0.60 N·m84 oz·in15,9151.0050,000N/Astep
1 WB 431.50 N·m13 lb·in95501.550,00065,000S pdf | HS pdf |
IS pdf | MB pdf | step
2 WB 433 N·m26 lb·in9550350,00065,000S pdf | HS pdf |
IS pdf | MB pdf | step
1 WB 6510 N·m88 lb·in5730630,00050,000S pdf | HS pdf |
IS pdf | MB pdf | step
2 WB 6520 N·m177 lb·in57301230,00050,000S pdf | HS pdf |
IS pdf | MB pdf | step
1 WB 11550 N·m36 lb·ft28651518,00022,000step
2 WB 115100 N·m73 lb·ft28653018,00022,000step
1 WB 15140 N·m103 lb·ft2390357500N/AMB pdf | step
2 WB 15280 N·m206 lb·ft2390707500N/Astep
3 WB 15420 N·m309 lb·ft23901057500N/Astep
4 WB 15560 N·m413 lb·ft23901407500N/Astep

Key to PDF Drawing Abbreviations

CodeDynamometer Option
SStandard Dynamometer
HSHigh Speed (WB Series only)
ISIndustrial Version
MBMechanical Rotor Blocking Device (WB Series only)
DGSpeed 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.

ModelDescriptionHysteresis Dynamometers (including ED Series)Eddy-current DynamometersPowder Brake DynamometersDial Weight Dynamometers
DSP7000High-Speed Programmable Dynamometer Controller
6200Dynamometer Controller/Readout
TSC 401Torque/Speed Conditioner
5500Dynamometer Switch Box
5501Dynamometer Switch Box
M-TEST 7Motor Testing Software
DES 410/411Power Supply
5241Power AmplifierRequired for HD-825 Only
5200Power Supply
5210Current-Regulated Power Supply
5250Current-Regulated Power Supply
TABDynamometer Tables
AMFAdjustable Motor Fixtures
FMFFixed Motor Fixtures
PTT-Slot Base Plate
FRSFree-Run Speed Sensor
SBB 14Signal 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



WB/PB 43 Seriespdf
WB/PB 65 Seriespdf
1–2 WB 65 + K + 1–2 PB 65pdf
2 WB 65 + MK + 2 WB 65pdf
WB/PB 115 Seriespdf
2 WB 115 + K + 2 WB 115pdf
WB/PB 15 Seriespdf

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)xn (rpm)x(1.047 × 10-1)
English:P (watts)=T (lb·in)xn (rpm)x(1.183 × 10-2)
Metric:P (watts)=T (kg·cm)xn (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.