The Opera-BH (OBH) is a heavy-duty industrial jackshaft for standard, high and vertical lift sectional doors, rolling doors and grilles, and its signature is the manual operation. Where most of the range uses a floor-level engaging device you must set before hand-chaining the door, the OBH carries Manaras’ Hoist-a-matic self-engaging hoist: grab the chain and go, no engagement step, plus a manual egress release. An electrical interlock still cuts motor power automatically the moment the hoist or egress is engaged.
What This Operator Suits
Heavy-duty applications where manual operation actually gets used, buildings where power interruptions, egress requirements or operational habits mean staff hand-chain the door often enough that the engagement dance on a standard hoist becomes a daily annoyance. Fire halls, works yards and service buildings are typical homes.
Specification
| Item | Detail |
|---|---|
| Motor | 60Hz high starting torque, continuous-duty, single-phase capacitor start or 3-phase, open drip proof, overload protected (50Hz variants available) |
| Reduction | 5L/B V-belt first step, chain and sprockets after; 5/8″ input shaft and 1″ output shaft with 1/4″ keyway on precision ball bearings; output 41 rpm |
| Drive | #41 roller chain, 41B12 operator sprocket; door sprocket for 6–12″/sec travel |
| Clutch | Friction type on input shaft, adjustable from outside |
| Brake | Mechanical brake |
| Manual operation | Hoist-a-matic self-engaging chain hoist with automatic motor cut-off, plus manual egress release; hoist right standard |
| Limits | Rotary cam limits with Accu-cam one-hand adjustment |
| Enclosure | Nema 1, hinged cover |
| Control | BOARD 070, monitored entrapment protection, ANSI/CAN/UL 325 compliant |
Duty rating in plain terms. Heavy-duty jackshaft with the friendliest manual operation in the range.
What Fails on This Unit
V-belt tension, the friction clutch and the mechanical brake are the routine points. The Hoist-a-matic mechanism itself is robust, but its electrical interlock is a diagnostic gotcha: if the interlock switch fails or sticks after someone hand-chained the door, the operator is left electrically dead and presents as a power or board fault. When an OBH “just died” right after a power cut, during which somebody inevitably hand-chained the door, the interlock is the first thing worth checking, not the last.
Manufacturer Documents
Related jackshafts: OSH, OMH, and the heavy-duty OPH/OHJ.
Choosing Between Models
If you are unsure which unit you have, the model code is on the data plate on the operator housing. Note the voltage and phase while you are there, and roughly how many cycles a day the door runs, those three facts decide most of what we would bring to a call.
See the full Manaras model reference for the whole range, or Manaras operator repair for service.
Parts and Accessories
Pairs with the full accessory range: photo eyes, light curtains and sensing edges, radio controls, control stations and traffic lights. One point that causes repeated confusion: on a UL 325 monitored circuit, a failed safety device makes the operator refuse to close. That is correct behaviour, not a malfunction. A door that suddenly will not close, with no other symptom, is very often a photo eye or sensing edge that has failed or drifted out of alignment.