The OMJ is the medium-duty jackshaft with a floor level disconnect rather than a chain hoist. Mechanically it is the same operator as the OMH, same motor, same reduction, same 36 rpm output, and the difference is entirely in how the door gets moved by hand.
What This Operator Suits
Standard, high and vertical lift sectional doors, small rolling doors and grilles. Wall, hood or shelf mounted either side of the opening.
This is the right choice when manual operation during a power failure is either not required or is handled another way. A warehouse with a second bay, a parkade with a pedestrian exit and a gate that can wait, those buildings do not need to pay for the Hoist-a-matic. Where staff genuinely must open the door by hand, specify the OMH instead.
Specification
| Item | Detail |
|---|---|
| Motor | 1/2 HP, 120V single-phase, intermittent-duty, open type with instant reverse and internal automatic reset thermal overload protection (60Hz) |
| Output shaft speed | 36 rpm |
| Drive | #41 roller chain with 41B12 sprocket |
| Reduction | 5L/B V-belt first step, then chain and sprockets. 5/8″ input, 1″ output shaft with 1/4″ keyway |
| Brake | Mechanical brake |
| Manual operation | Floor level disconnect mechanism |
Duty rating in plain terms. Medium duty on a standard 120V circuit.
What Fails on This Unit
Same friction clutch as the OMH, same outside adjustment. The difference in service terms is the disconnect: a floor level disconnect gets pulled, gets left disengaged, and then the door ‘stops working’ when in fact the operator is simply disconnected from it. Before anything else, check the disconnect is re-engaged, we have attended calls where that was the entire fault.
Manufacturer Documents
Originals from Manaras-Opera, useful if the paperwork for a unit already in your building has gone missing:
Choosing Between Models
The OMH is this operator with the Hoist-a-matic chain hoist fitted. 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
Manaras publish a full accessory range that pairs with this operator: monitored and non-monitored photoelectric cells, light curtains, electric and pneumatic sensing edges, interface modules, push-button and key switch control stations, pull switches, keypads and card readers, radio receivers and transmitters, and traffic light kits.
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.
- Accessory catalogue (PDF)
- Accessories and replacement components list (PDF)
- Radio Series 900 dip-switch compatibility chart (PDF)
- Radio Series 100 rolling code compatibility chart (PDF)
- Operator codes explained (PDF)
We stock the common wear items for the Opera and MEGA series, control boards, clutches, solenoid coils, limit switch assemblies and safety edges. Anything we do not carry we source through our distributor, and you will hear about a lead time before we attend rather than after.
Frequently Asked Questions
How do I confirm I have a OMJ?
The model code is on the data plate on the operator housing. If the plate is unreadable, which happens on older units in damp parkades, send us a photo of the operator and we can usually identify it from the frame and drive layout.
Do you stock parts for it?
We carry the common wear parts across the Opera and MEGA series. Model-specific components come through our distributor, typically within two business days.
Is it worth repairing or should we replace it?
Clutches, brakes, boards, limits, safety devices and wiring are repairs. A seized gear reducer or a burnt-out motor on a very old unit is usually a replacement. We tell you which one you are looking at and why, rather than leading with a new-operator quote.
Can you service a unit we did not buy from you?
Yes. Most Manaras units we attend were installed by someone else, often years ago.
The door will not close but opens fine. Is the operator dead?
Almost certainly not. That is the classic monitored safety circuit symptom, a photo eye, light curtain or sensing edge that has failed or moved. Check the lenses are clean, the alignment is good, and nothing is parked in the beam before assuming the worst.