A Technical Description of a
Variable Speed Generator System
for retro­fitting RTG Cranes
Non­Synchronous Energy Electronics, LLC
94 Middlesex Rd.
Merrimack, NH
03054 USA
1 (603) 546­5785
www.nonsynchronous.com
Existing RTG Electrical System
Non­Synchronous Energy Electronics
Engine
Generator Set
A fuel saving Variable Speed Generator System can be incorporated into existing RTG Cranes
Aux. Loads
For Existing Generator Sets, the engine speed can only be governed from 47Hz to 63Hz, with an idle speed of between 750 RPM and 900 RPM
The NSEE System makes use of the idle/running toggle with trim signals to optimize performance
For a 50Hz system such a Detroit Series 60 Engine, a further improvement in peak power of about 60kW can be incorporated for heavy lifts
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Trolley
Hoist
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Gantry
RTG with VSG and Bypass Switchgear
Non­Synchronous Energy Electronics
Engine
Generator Set
Aux. Loads
DC Boost Control
(+)
(­)
The VSG System is added, without removing any of the existing equipment.
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The Bypass Switchgear can be used to switch back to the original mode of fixed generator speed operation
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Trolley
Hoist
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Gantry
The Engine and Alternator controls have a similar bypass mode to change when the power switchgear changes
RTG with VSG System, Energy Storage and Bypass Switchgear
Non­Synchronous Energy Electronics
Engine
Generator Set
Aux. Loads
The Energy Storage System is added directly to the DC Link
Battery
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Trolley
Hoist
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Gantry
RTG with Smaller Generator, VSG , Energy Storage and NO
Bypass Switchgear
Non­Synchronous Energy Electronics
Engine
Smaller Generator Set
Aux. Loads
Once the System is proven and accepted, the bypass can be removed and a smaller generator put in place for maximum fuel savings
Battery
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Trolley
Hoist
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Gantry
Non­Synchronous Energy Electronics
VSG – Generator control interface diagram
Toggle idle/rated Speed
Speed Trim
V fb
AVR
PMG
Field
Current
Controller
Field Current Supply
VSG
Throttle
Control
Speed fb
Field
Engine
Generator Set
Example of similar Power Converters;
Non­Synchronous Energy Electronics
A VSG Power Converter rated 500kW, 300% O/L
NSEE has an exclusive agreement with;
Custom Power Technology Inc.
of Menomonee Falls, Wisconsin
to supply the custom designed Power Converters for the RTG crane VSG Ststems
30 similar units are running on the Chicago Metro Rail system
Traction Duty Construction!