HYDM390M Hydraulic Motor | 2.38 cid Marzocchi

HYDM390M Marzocchi LSHT Hydraulic Motor

System Role & Intended Duty

• Marzocchi external-gear, low-speed/high-torque hydraulic motor with 2.379 in³/rev (≈39.0 cc/rev) displacement.
• Engineered to drive mid- to larger-frame Annovi Reverberi (AR) triplex plunger pumps where controlled speed and high torque are required.
• Designed for direct hydraulic drive applications that eliminate belts, pulleys, and tensioning systems.
• Optimized for industrial wash systems installed on skids, service trucks, trailers, vans, plant carts, and utility platforms with existing hydraulic power.

HYDM390M Motor Architecture & Operating Characteristics

• External-gear LSHT construction delivers high starting torque and smooth rotational output.
• Displacement supports moderate pump speeds without demanding excessive hydraulic flow.
• Stable torque delivery promotes consistent working pressure and calm trigger response.
• Round-body geometry simplifies packaging in tight compartments.
• Well suited for intermittent and continuous-duty pressure washing cycles.

HYDM390M Mounting & Alignment Strategy

• Intended for coaxial mounting with the AR pump on a shared rigid base.
• Shared centerline minimizes side loading on pump bearings and seal packs.
• Alignment-stable geometry reduces vibration compared with belt-driven systems.
• Close-coupled layout preserves access to coupling hardware, fasteners, oil sight glass, and vented dipstick.
• Perimeter space remains available for short suction runs and clean pressure and bypass routing.

Hydraulic Ports & Circuit Interface

• Typical hydraulic ports are SAE-12 ORB (3/4″) for pressure and return.
• Many supplied motors include an auxiliary SAE-8 ORB (1/2″) case drain; verify on the furnished build.
• If present, the case drain must return to the reservoir above oil level and remain unrestricted.
• A/B port orientation must be observed so motor rotation matches pump rotation.
• Hose IDs must be generously sized and minimum bend radii respected to prevent restriction and heat buildup.

Hydraulic Sizing & Shop Math

• Motor speed: rpm ≈ 231 × hydraulic GPM ÷ displacement (in³).
• With 2.379 in³ displacement, speed is approximately 97 × hydraulic GPM.
• At 6 GPM, shaft speed is approximately 580 RPM.
• At 8 GPM, shaft speed is approximately 775 RPM.
• Torque: lb-in ≈ displacement (in³) × PSI ÷ 6.283.
• At 2,500 PSI, estimated torque is approximately 950 lb-in.
• At 3,000 PSI, estimated torque is approximately 1,140 lb-in.
• Hydraulic power: HP ≈ GPM × PSI ÷ 1714; apply realistic system and motor efficiency.

Hydraulic Circuit Protection

• Upstream relief valves must be set correctly for the intended operating pressure.
• 10–25 μm return filtration with an adequate beta rating is required.
• Reservoir volume should follow a practical rule of 2–3× total system flow.
• Oil cooling is recommended for hot climates, prolonged bypass operation, or continuous duty.
• Hose routing must avoid sharp bends, restrictive fittings, and unnecessary adapters.

HYDM390M Water-Side Plumbing Requirements

• Suction plumbing must be short, straight, and oversized from a flooded source.
• Anti-collapse suction hose and a coarse inlet strainer are required to prevent cavitation.
• An adjustable unloader matched to the AR pump duty class is required.
• A correctly sized high-pressure relief valve is required as a secondary safety device.
• A glycerin-filled pressure gauge is required for commissioning and diagnostics.
• A thermal relief valve is required on the bypass loop for extended gun-closed operation.
• The pump must never be over-sped and must never be run dry.

Compatible AR Pump Classes

• Well suited for mid- to larger-frame AR triplex pumps.
• Typical operating ranges include 5–13 GPM at 1,500–4,000 PSI.
• Applications prioritize smooth pressure response and controlled flow.
• Pump selection must always respect published maximum RPM limits.

Service Access & Reliability

• Close motor-to-pump spacing preserves access to coupling hardware and service points.
• Single-technician maintenance is supported for coupling checks, oil changes, and torque verification.
• Rigid base geometry maintains alignment through transport, temperature swings, and daily use.
• Reduced vibration and side loading extend bearing and seal life.

Typical Applications HYDM390M

• Mobile wash skids on service trucks and trailers.
• Municipal and DOT fleet maintenance facilities.
• Heavy-equipment yards and rental turn-back operations.
• Marine and tug-boat dock washdown systems.
• Plant carts, conveyor rinse cells, and parts-cleaning stations.
• Contractor and industrial systems where hydraulic power is already available.

HYDM390M Hydraulic Motor | 2.38 cid Marzocchi

System Advantages

• Direct hydraulic drive eliminates belts, belt dust, and re-tensioning requirements.
• Compact footprint supports clean, repeatable OEM layouts.
• Smooth LSHT torque delivers stable pressure and calm trigger cycling.
• Predictable hose routing simplifies documentation and future service.
• Professional, alignment-stable architecture improves uptime and lifecycle cost.