Models and Key Specifications
The OMH is a single model line; handing (hoist on right or left) must be specified at order time. The table below captures the factory data we reference on every install and service call.
| Item | Detail |
|---|---|
| Motor | 1/2 HP, 120 V single-phase, 60 Hz, intermittent-duty, open type with instant reverse and internal automatic-reset thermal overload |
| Output shaft speed | 36 rpm |
| Drive | #41 roller chain with 41B12 sprocket; door sprocket selected for 6 to 12 in/s travel |
| Reduction | First step 5L/B V-belt; additional steps by chain and sprockets |
| Shafts | 5/8" input, 1" output with 1/4" keyway, precision ball bearings |
| Brake | Mechanical |
| Manual operation | Hoist-a-matic self-engaging chain hoist with automatic cut-off and electrical interlock (right-hand standard) |
| Mounting | Wall, hood or shelf, either side of opening |
| Duty rating | Medium duty |
Because it runs on a standard 120 V circuit, the OMH is a frequent retrofit in older buildings that never had three-phase power run to the door.
Typical Applications
We see the OMH on standard-lift, high-lift and vertical-lift sectional doors, small rolling doors and grilles, and rolling sheet doors. The Hoist-a-matic makes it the default choice for shipping bays that cannot wait for power restoration and for strata parkades where the overhead door is the only vehicle exit.
What Fails and How We Repair It
Friction clutch wear
The input-shaft friction clutch is the primary wear item. It adjusts from outside the housing , no teardown required. On a medium-duty door, a slipping OMH is often an adjustment call, not a parts replacement.
Hoist handing mismatches
The hoist ships on the right unless left-hand is specified. If the operator was ordered without confirming the mounting side, the chain hangs in an awkward spot. This is an ordering oversight, not a defect, but it generates service requests we resolve by relocating the hoist assembly.
Choosing Between OMH and OMJ
The OMJ is the same operator with a floor-level disconnect instead of the Hoist-a-matic. If no one needs to hand-crank the door, the OMJ costs less. When we arrive on site, we check the data plate for model code, voltage, phase and approximate daily cycles , those three facts determine what parts and adjustments we bring.
Parts and Accessories
Manaras supplies a full accessory range for the OMH: monitored and non-monitored photoelectric cells, light curtains, electric and pneumatic sensing edges, interface modules, push-button and key-switch stations, pull switches, keypads, card readers, radio receivers and transmitters, and traffic-light kits. One recurring point of confusion involves UL 325 compliance , we verify the correct combination of monitored devices for each installation.
Getting Service in Metro Vancouver
Up and Down Garage Doors is an authorized Manaras dealer. We supply new OMH operators, genuine replacement parts, and on-site service across Richmond, Vancouver, Burnaby, Surrey and the surrounding municipalities. If you need a clutch adjustment, a hoist relocation, or a complete operator swap, we carry the stock and the manuals to finish the job in one visit.
Call 778-873-7282 to schedule a service call or request a quote , pricing is quoted per project.
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