The MGH is the large-frame worm gear operator: 40:1 reduction in an oil bath, output shafts up to 1-3/8″, and the option of #60 chain instead of #50. It is specified for the heaviest doors in the range.
What This Operator Suits
The largest industrial rolling and sectional doors. Available in multiple HP configurations, with totally enclosed TEFC or TENV motors on the 2 to 3 HP builds, which matters in dusty, damp or wash-down environments where an open drip proof motor would not survive.
The drive detail tells you where the line sits: 50B12 sprocket up to 1-1/2 HP, 50B15 above that, with #60 roller chain available as an option. If you are replacing an MGH, matching the sprocket and chain to the existing drive shaft is part of the job.
Specification
| Item | Detail |
|---|---|
| Motor | 60Hz high starting torque, continuous-duty industrial, single-phase capacitor start or 3-phase, open drip proof with enclosed ends or drip cover; totally enclosed TEFC or TENV on 2-3 HP |
| Reduction | 40:1 worm gear in oil bath reducer with air breather and sealed ball bearings |
| Output shaft | 1-1/4″ with 1/4″ keyway up to 1-1/2 HP; 1-3/8″ with 5/16″ keyway above 1-1/2 HP |
| Drive | #50 roller chain, 50B12 sprocket up to 1-1/2 HP, 50B15 above; #60 roller chain optional |
| Brake | Electrically activated drum-band solenoid brake; brake motor optional |
| Manual operation | Emergency manual chain hoist with floor level engaging device and electrical cut-out |
Duty rating in plain terms. Very heavy industrial.
What Fails on This Unit
Same oil bath discipline as the OGH, level, condition, and a clear air breather. On the totally enclosed motor variants, check that the enclosure is actually sealed; TEFC and TENV motors get specified for a reason and a cracked housing in a wash-down bay defeats the purpose.
With #60 chain builds, confirm the replacement chain and sprocket match what is fitted rather than what the base spec says.
Manufacturer Documents
Originals from Manaras-Opera, useful if the paperwork for a unit already in your building has gone missing:
Choosing Between Models
The MGT is the trolley version; MGSL the sliding door version. 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 MGH?
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.