Jump to Contact Us page, or phone 1-603-226-3966
Jump to Contact Us page, or phone 1-603-226-3966 Show Menu

Below are charts that explain the advantages of various configurations.

"Call for free technical assistance on selecting your own system."

Pick the best style dynamometer for your application! Each type of configuration has its own strengths and weaknesses. Our Dyno-Selector Wizard  and the chart below attempt to point out some of the more significant differences.

Custom hybrid configurations using a combination of both an AC Motor/Generator and Eddy-Current (or water brake) absorber can provide the unique characteristics of each - in a single installation. This means it is practical to have instantaneous control, stability, motoring capability, and high power absorption that would be otherwise unaffordable (or impossible) to duplicate. Control of the pair is done using DYNO-MAX “Pro” software. In very high Hp installations it is possible to reduce, significantly, both the dynamometer’s cost and inertia via this method.

Feature Water Brake Absorbers Inertia
Rollers
Inertia+
Parasitic
Fan/Pump
Air-Cooled Eddy Current
Absorbers
Liquid-Cooled Eddy Current
Absorbers
Friction Brakes Hydraulic Pumps

AC Motor- Generators

DC Motor- Generators
High Hp (steady state) capacity? Excellent n/a* Fair
(depends on fan size)
Good Excellent Poor
(cooling required
Fair
(cooler required
Good Fair
High RPM capability? Excellent n/a Fair
(fan limited)
Fair Excellent Good Poor Fair Poor
Low RPM torque
(steady state) capacity?
Fair n/a* Poor Very Good Very Good Excellent Excellent Excellent Excellent
Stall torque
(0 RPM range)
test capability
?
Poor Fair
(startup only)
Fair
(startup only)
Poor Poor Very Good Very Good Excellent
(with encoder)
Excellent
(with encoder)
Stability of
RPM load control?
Good n/a* n/a*
(exponential
fixed curve)
Very Good Very Good Poor Very Good Excellent Very Good
Typical response time to 90% load change? Good
(less than 0.5 seconds)
n/a* n/a*
(exponential
fixed curve)
Very Good
(less than 0.1 seconds)
Very Good
(less than 0.1 seconds)
Poor
(less than 1.0 seconds)
Fair
(less than 0.75 seconds)
Excellent
(less than 0.01 seconds)
Excellent
(less than 0.01 seconds)
Testing simulation under computer control? Good n/a* n/a*
(exponential
fixed curve)
Excellent Excellent Fair Not typically available Excellent Excellent
Motoring capability? requires separate motor requires separate motor requires separate motor requires separate motor requires separate motor requires separate motor requires separate motor Excellent Excellent
Suitability to long duration testing? Excellent n/a* Excellent Fair Excellent Fair
(water cooled)
Good
(with cooler)
Excellent Good
Ease of engine starting? requires separate starter requires separate starter requires separate starter requires separate starter requires separate starter requires separate starter requires separate starter Excellent Excellent
Hp capacity
vs. weight?
Excellent Poor Poor Fair Fair Fair Fair Poor Poor
Hp capacity
vs. size?
Excellent Excellent Excellent Fair Good Good Good Fair Poor
Portability of
absorption unit
Excellent Determined by weight Determined by weight Fair Poor Fair Good Poor Poor
RPM, Torque, &  Hp Accuracy? Determined by Data Acquisition Determined by Data Acquisition Determined by Data Acquisition Determined by Data Acquisition Determined by Data Acquisition Determined by Data Acquisition Determined by Data Acquisition Determined by Data Acquisition Determined by Data Acquisition
Data Repeatability? Determined by Data Acquisition Determined by Data Acquisition Determined by Data Acquisition Determined by Data Acquisition Determined by Data Acquisition Determined by Data Acquisition Determined by Data Acquisition Determined by Data Acquisition Determined by Data Acquisition
Resistance to hysteresis (breakaway friction) Good Excellent Excellent Very Good Very Good Good Poor Very Good Good
Immunity to un-trunioned parasitic drag losses Excellent
(if mounted directly)
Poor Poor Good Excellent Good Fair Excellent
(with in-line transducer)
Excellent
(with in-line transducer)
Affordability per Hp
(steady state) capacity?
Excellent n/a* Fair Good Fair Fair Fair Poor Poor
Installation affordability? Excellent
(if water is available)
Fair
(if pit or lift required)
Fair
(if pit or lift required)
Very Good
(115v AC required)
Good
(115v AC required)
Good
(but cooler required)
Good
(but cooler required)
Fair
(electrician required)
Fair
(electrician required)
Affordability of  maintenance? Excellent Excellent Excellent Excellent Very Good Fair Good Excellent Good

*n/a - not applicable, inertia-only "dynos" can not directly measure torque or maintain a steady state load (without also being equipped with some form of absorber and load cell or a parasitic drag source (e.g. a large fan or pump with a known loss curve).