Technology
A mechanical battery built to be maintained, not sealed.
Dorcasey's DT-10 kW design stores energy in a spinning alloyed-steel flywheel and returns it through the permanent-magnet DC motor-generator used to spin it up. It is designed to reduce cost and simplify maintenance.
Key specifications · DT-10 kW system
70.9 kWh
Nameplate DC capacity
60.97 kWh
Usable @ 86% efficiency
9.68 kW
Usable DC output
6 h
Discharge duration
260 min
Full recharge time
600 kg
Alloyed steel flywheel
Design approach
Twelve design decisions, six that matter most.
Speed over mass
Higher angular velocity with a lighter 600 kg rotor stores more energy than a 2,250 kg disc turning slowly. The modified solid Laval disc profile raises the shape factor to 1.0 against 0.5 for a regular solid disc.
Spin above synchronous speed
The flywheel turns at 15,000 rpm while its motor-generator is rated at 10,000 rpm, with the horizontal layout taking advantage of gravitational loading.
No vacuum, no magnetic bearings
Both are costly, maintenance-heavy, and draw continuous power. The design avoids them, holding specified ancillary draw to about 50 watts and keeping the machine serviceable in the field.
Simple, permanent-magnet DC machine
A permanent-magnet DC motor-generator reduces structural complexity compared with asynchronous AC arrangements, and supports DC or single/three-phase AC output points.
Energy-mix input
Wind, solar, geothermal, hydro, or grid power can kick-start the system, which allows standalone and remote installations.
Multiple system sizes
The same mechanical arrangement can be sized for applications ranging from farm equipment to remote industrial sites.
Comparative analysis
Measured against two established flywheel products.
| Metric | DT-10 kW | Amber Kinetics A32 | PLUS SMS UPS series |
|---|---|---|---|
| Nameplate DC capacity | 70.9 kWh | 32.0 kWh | 1.72 kWh |
| Usable energy @ 86% | 60.97 kWh | 27.52 kWh | Not reported |
| Usable DC power output | 9.68 kW | < 8 kW | 51.67 kW |
| Output duration | 6 hours | 4 hours | < 2 minutes |
| Flywheel mass | 600 kg | 2,250 kg | Not reported |
| Flywheel speed | 15,000 rpm | 9,000 rpm | 10,000 rpm |
| Clutch system | Yes | No | No |
| Vacuum system | Not required | 10–50 torr | 10–50 torr |
| Ancillary load draw | 50 W | 300 W | 350 W |
| Primary input source | Wind, solar, geothermal, hydro, grid | Grid or AC source | Grid or AC source |
Source: Dorcasey internal comparative analysis. DT-10 figures are design specifications, not test results from a built 10 kW unit.