What is Under Driven vs Over Driven?

It describes where the input worm sits relative to the output wheel. Under Driven: worm below the wheel. Over Driven: worm above. Oil level, seals and mounting change with it.

Do I need a different gearbox to switch orientation?

Not on the Anand Gears NU series. The same single-piece universal casing installs Under Driven or Over Driven. Adaptable units instead use six interchangeable shaft positions on a foot-mounted casing.

NU centre distances 60, 72, 84, 100, 127, 152, 180 and 205 mm, ratios 5:1 to 70:1, power to 22 kW. See the NU series page for the size table.

Can you convert an existing unit?

Orientation conversions, including fitting LH and making Over Driven RH, are a documented special practice. Confirm lubrication and nameplate orientation on the order.

Under Driven and Over Driven Worm Gearboxes

Name: Under Driven and Over Driven Worm Gearboxes
Brand: Anand Gears

Same NU casing, two mounting arrangements. Worm below the wheel or above it — oil level and seals set to match. Centre distances 60 to 205 mm.

Anand Gears Under Driven worm gearbox with solid foot mounting

NU Orientation

One Casing, Two Arrangements

Under Driven puts the worm below the wheel. Over Driven puts it above. The Anand Gears NU series uses a single-piece universal casing, so the same gearbox body covers both. That is why one spare on the shelf can serve machines that were piped differently years apart. Ratios 5:1 to 70:1, centre distances 60 / 72 / 84 / 100 / 127 / 152 / 180 / 205 mm, power to 22 kW. For six shaft positions on a foot-mounted casing, see Adaptable.

NU series sizes Get a budgetary offer

Where It Runs

When orientation matters

Conveyors

The drive is flipped under or over the belt frame when the plant layout changes. Same NU spare covers both.

Mixers and agitators

Vertical-up or vertical-down output is a separate arrangement; Under/Over Driven is the worm-to-wheel relationship on the right-angle casing.

Conversions

LH to Over Driven RH and similar orientation conversions are standing specials — confirm lubrication on the order.

FAQ

Under Driven / Over Driven

Do I buy two models?

Not for NU. Specify the orientation on the order so oil level and nameplate match how it will sit.

Is Top-Bottom the same thing?

No. Top-Bottom is a further special arrangement. Ask for it by that name. See Custom & Special Gearboxes.

Budgetary offer — Under Driven / Over Driven Worm Gearboxes

Tell us the duty and we’ll send you a number

Power, input speed, and either the ratio or the output speed you need are usually enough to start. Our engineers reply on the same working day.

Have a nameplate photo, a drawing, or the old unit in front of you? Send it on WhatsApp — that is the fastest route to a number.

Prefer to talk? +91 98203 83719 or +91 98205 18093.