Case Study

275-Ton Gantry Crane Modernization at a Hydroelectric Dam: AC Drive Conversion, Radio Controls, and Full Code Compliance

Industry: Energy

A major Northeastern hydroelectric power authority was operating two 275-ton gantry cranes, the North Crane and South Crane, that were decades old, out of compliance with current OSHA, CMAA, and NEC codes, and deteriorating to the point where continued operation presented serious safety and infrastructure risks. The cranes served a critical function: positioning water control gates at the dam, a task that demands both precision and reliability. An independent engineering study by Simmers Crane Design & Services Co. documented the full scope of mechanical, structural, and electrical deficiencies across both cranes, including worn hoist components, corroded gantry leg structure, failing brake systems, and an aging DC drive system incapable of delivering the precise, variable-speed gate positioning the facility required. The authority needed both cranes brought back to full operational confidence, and they needed it done without replacing the cranes entirely.

Han-Tek won the contract to modernize both cranes: a comprehensive scope covering electrical and drive systems, mechanical repairs, structural repairs, OSHA compliance, and radio controls on both the North and South Cranes.

Their Challenge:

Two 275-ton P&H gantry cranes (North Crane and South Crane) required full mechanical, structural, and electrical modernization to meet current OSHA, CMAA, and NEC standards. Continuing to operate them in their existing condition was no longer acceptable.
The original DC drive system on both cranes could not deliver the precise, variable-speed control required for reliable water gate positioning. Dam-level gate management demands accurate, repeatable positioning, a requirement the aging DC system could no longer meet.
Both cranes required operators to perform routine operation and maintenance tasks at dangerous working heights. With no remote control capability, personnel exposure at height during every operational cycle was unavoidable.
A Simmers Crane Design & Services engineering study documented extensive mechanical and structural deficiencies across both cranes: worn truck saddle pins, deteriorated hoist drum components, failed gear box oil seals, worn brake systems, structural weld failures in gantry legs and end ties, and rope and sheave wear throughout both hoist systems.
OSHA compliance deficiencies spanned both cranes: missing wind anemometers and rail clamps, unrated load markings, cage deficiencies, and inadequate environmental protection across the operating environment.

Our Solution:

Han-Tek designed, engineered, procured, and installed the complete modernization of both 275-ton gantry cranes, covering all crane motions, all electrical systems, all required mechanical repairs, and full OSHA compliance work on both the North Crane and South Crane.
Magnetek VG+ series AC variable-frequency drives were installed on the main hoist and auxiliary hoist motions of both cranes, and Magnetek G+ series drives were installed on the bridge, trolley, and gantry motions, replacing the original DC drive systems entirely and enabling infinitely variable speed control across all five crane motions for precise, repeatable gate positioning.
Cattron Theimeg MP96 radio control systems were installed on both cranes, allowing operators to control all crane motions from the safe dam level, completely eliminating the need for personnel to work at dangerous heights during normal crane operation.
New crane motors were specified and supplied for all motions on both cranes (main hoist, auxiliary hoist, trolley, and gantry drive) and matched to the new Magnetek AC drive systems. New SEW Eurodrive gear reducers were installed on the drive motions, and new Hillmar/Mondel braking systems replaced the original hydraulic brakes and brake solenoids throughout.
New EMS festoon cable management systems were installed on both cranes, and new Cutler-Hammer disconnect switches and control panels were engineered and installed to bring the full electrical systems to current NEC standards. Load cells were specified and installed on both cranes for integrated load monitoring.
OSHA compliance work was completed across both cranes: wind anemometers and rail clamps were added to the bridge structures, rated load markings were applied, cage modifications were made, and all required safety items identified in the Simmers study were addressed.
Mechanical and structural repairs documented in the Simmers Crane Design engineering study were completed on both cranes: truck saddle pin replacement with redesigned pins, hoist drum and sheave repairs, gear box oil seal replacement, brake system restoration, complete crane lubrication, hoist rope replacement, and structural weld repairs to gantry legs, end ties, and bumper plates per the NDT findings. Drip pans and new light fixtures were also installed to address the environmental and maintenance accessibility issues on both cranes.
Han-Tek acted as single-point contractor for the full scope, managing P&H as the crane OEM partner for structural and mechanical work and coordinating all equipment suppliers across a multi-phase modernization of two active infrastructure cranes.

The Results:

Water gate positioning accuracy restored: Magnetek variable-frequency drives on all five motions of both cranes deliver the precise, variable-speed gate positioning the original DC system could not achieve, restoring full operational confidence in dam water-level management.
Personnel safety at height eliminated: Cattron Theimeg MP96 radio controls allow operators to run both cranes entirely from the dam level, completely eliminating the personnel exposure at dangerous heights that had been unavoidable under the original system.
Full OSHA, NEC, and CMAA compliance achieved: Both 275-ton cranes now meet current codes across all electrical, mechanical, and structural systems, eliminating the compliance risk that had been building across decades of deferred modernization.
Mechanical reliability restored across both cranes: Every deficiency identified in the Simmers Crane Design engineering study, including worn hoist components, truck assemblies, gear boxes, brake systems, and gantry leg structural repairs, was addressed, significantly reducing the maintenance burden going forward and restoring structural confidence in both crane frames.
Critical infrastructure preserved without replacement: Both cranes were fully modernized in place, bringing two 275-ton gantry cranes to like-new operating condition at a fraction of the cost and disruption of complete crane replacement.

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