The SAE A keyed build of the Caproni 20MR group 2 gear motor: a 2 bolt SAE A flange with a 5/8 inch parallel keyed shaft for US-pattern conveyor, auger and brush drives. Bulgarian-made with the reinforced 30 bar shaft seal, bi-directional, 11 displacements from 4.5 to 28 cm3/rev.

Pick a displacement below and the exact factory part number and price appear on screen. Every choice in the dropdown is a real catalogued part number we can order today.

Specifications and Part Numbers

SAE A 2 Bolt Mount - 5/8 inch Keyed Shaft

Standard Supply Configuration

• Bare motor, bi-directional rotation — no valve block, fittings or adaptors fitted
• BSPP inlet, outlet and case drain ports, sizes per the specification table for your displacement
• Mounting flange and output shaft exactly as selected in the dropdowns above
• Shaft seal is rated for case pressure only — the case drain must be plumbed back to tank on its own line
• Supplied as a single motor; seal kits are listed separately

Performance data, the how-to-choose guide and the full range live on our main Caproni 20MR page:

Technicians Advice

Fit the coupling or sprocket, never hammer it. A parallel keyed shaft takes the drive with a light interference or a slip fit and a grub screw on the flat - hammer blows land straight on the bearings, and a motor lives on its bearings.

A gear motor is not a gear pump run backwards. People try it every week and wreck them. A motor has a case drain and a shaft seal rated for low pressure only; a pump has neither. Run a pump as a motor and the first thing that happens is the shaft seal lets go. Run a motor as a pump and it will do it, badly, until the bearings give up. Buy the right one.

The drain line decides how long it lives. The case port must go back to tank on its own line, full bore, no restrictors, no tee-ing into a pressurised return. The drain pressure limit on these is 6 bar — that is nothing. If you have to run a long drain line, go up a hose size.

Overrunning loads will cavitate it. Gear motors have almost no internal resistance, so anything with inertia — a flail head, a saw blade, a fan, a loaded conveyor — keeps driving the motor after you close the valve. It sucks air past the shaft seal and pits the gear faces. Fit an anti-cavitation check valve or a crossline relief. Vivoil offers the check valve as a factory option on the group 2 and group 3 frames; ask us.

Taper shafts: clean both surfaces dry, no grease, no anti-seize, and torque the nut properly. A taper hub that has been assembled greasy will work loose and then chew the taper, and the taper is part of the motor.

Do not overspeed the small ones. The group 1 frames will spin to 5,000 or 6,000 rpm but they also have a minimum speed around 700 rpm — below that a gear motor barely makes torque and runs rough. That is not a fault.

Complete your setup

Seal kits and the other builds of this motor:

Fitting out a fleet or buying several? Call us and we will work out freight and lead time on the whole lot.

Warranty and Service

12-month warranty on every motor. If you are identifying an existing motor, photograph every number cast or stamped on the body and the shaft end and send it through with your enquiry - gear motor part numbers are long and one letter changes the shaft or the rotation.

Shipping and Freight Information

We ship Australia-wide. Orders are dispatched from our supply network in Melbourne, Brisbane and Perth, so your parts leave from the warehouse closest to you on express freight. Because we sell solid steel components, freight costs reflect real weight and real distance. We do not hide freight costs in inflated product prices. What you see is what you pay.

Why Buy From Us

• 20+ years of hydraulics expertise
• Australian owned and operated, Gold Coast QLD - ABN 92 969 264 674
• Secure checkout: Visa, Mastercard, PayPal, Zip Pay, Direct Deposit
• Tax invoices supplied with every purchase
• Phone 07 5563 1982 or 1300 1 HOSES - Email sales@mhfgc.com.au

Out of Stock Policy

It is our intention to maintain active stock on every listed item at all times. On rare occasions a size may be temporarily unavailable. If this occurs you will be notified immediately and offered the choice of a full refund or a short wait for incoming stock, typically 3 to 14 days.