420Nm Rolling Shutter Central Motor, 250 KG in Oman

Description

The 420Nm central motor mounts on the shutter shaft rather than inside it, driving a 240mm pulley to lift up to 250 KG of curtain. That mounting is the whole point of the product. It automates shutters with a 76mm shaft, where a tubular motor simply will not fit inside the barrel.

Before ordering, measure one thing. The assembly is roughly 240mm in diameter and hangs inside the shutter box, so a shallow box will not close over it. Clearance stops more of these installations than torque does.

Check 240mm of clearance before you order

A central motor is not a slim device. It sits on the barrel with the pulley and the drive housing around it, and the shutter box has to swallow all of it with the curtain rolled up beside it.

Open the box and measure the clear space around the shaft, then measure the fully rolled curtain diameter at the top of travel. Both have to live in there together. If your box is tight, the answer is usually a side mounted drive rather than a smaller central motor.

Send us a photograph inside the box with a tape measure across it and we will tell you before you spend anything. This takes two minutes and saves a return.

Central, tubular or side, which one your shutter takes

Three mounting types cover almost every rolling shutter in Oman, and the choice is made by your barrel and your box, not by torque.

If your barrel takes it, compare this against the 92mm 450Nm tubular motor, which sits at the same price and hides completely inside the tube. For heavy warehouse curtains beyond this range, see the 2000 KG side mounted motor. The full rolling shutter motor range carries all three.

420Nm but 250 KG, and why that is not a contradiction

Customers read the torque figure and the kilogram figure as the same claim. They are not. Torque is turning force at the shaft, and the curtain weight it lifts depends on how far out that force acts, which is the barrel and pulley radius.

Going from 260Nm to 420Nm gives 62 percent more torque but only 19 percent more rated lift. The extra torque is there to turn a larger rolled diameter, which is what a taller curtain builds up as it winds. In plain terms, this model is for tall shutters more than for unusually heavy ones.

So if your shutter is short and heavy, the 260Nm may be the correct and cheaper answer. If it is tall, this is the one. Give us the height and we will say which.

The specification, and what the maker does not publish

We list what is stated and we mark what is not, because guessing on a datasheet gap is how the wrong motor ends up on a wall.

We read the rating plate on the unit we are actually shipping and confirm the missing figures in writing before installation. Duty cycle and manual override are the two we always check, for the reasons below.

Power cuts, and the question the datasheet skips

Most central motors of this class carry a manual release with a chain or crank, so the shutter can be opened by hand when the power drops. This one does not say so anywhere.

That matters in Oman. A shop shutter that cannot be raised in an outage traps stock inside and a warehouse shutter traps vehicles. We confirm the override arrangement on the exact unit before we fit it, and if there is none we tell you rather than discover it on a bad day.

Electrical supply

It runs on ordinary 220V single phase, which is the practical advantage over three phase side motors. Almost any shop, compound or small unit in Oman can power it without a utility upgrade.

Because the current draw is not published, we size the circuit from the rating plate rather than assume. As a rule we give any shutter motor its own protected way and a local isolator within sight of the door, which is what a maintenance visit will need anyway.

What is included, and what is not

• Central motor and pulley assembly
• Fixings as supplied by the maker, contents not itemised by the manufacturer

Not included: control panel, up and down push button station, radio receiver, remote handsets, safety edge, photocells and cabling. Those come from shutter accessories and we quote them as one package so nothing is missing on the day.

Sized, supplied and fitted across Oman

We stock central, tubular and side mounted drives, so we have no reason to push you toward one type. Our engineers cover Muscat, Rusayl, Sohar, Nizwa, Sur, Duqm and Salalah, and we survey the box before quoting a retrofit.

Supply only is fine if you have a fitter. Browse the full Doors Auto catalogue, read our shutter motor guides, or send us the shutter height, shaft size and a photograph inside the box and we will confirm the right motor before you order.

Frequently asked questions

What is the difference between a central motor and a tubular motor? A central motor mounts on the outside of the shaft inside the shutter box, while a tubular motor hides inside the barrel. Choose central when the shaft is too narrow for a tubular motor and the box is deep enough to take a 240mm assembly.

Will it fit my shutter? It suits a 76mm shaft and needs roughly 240mm of clear space in the shutter box alongside the rolled curtain. Measure the box interior and the rolled curtain diameter, or send us a photograph with a tape measure across it.

Why is it rated 420Nm but only 250 KG? Torque is turning force and the kilogram figure is what that force lifts at a given barrel radius. The step up from 260Nm buys the ability to turn a larger rolled diameter, so this model suits tall curtains more than unusually heavy short ones.

Can I open the shutter by hand in a power cut? The manufacturer does not state a manual override for this model, so we confirm it from the actual unit before installation. If there is none we will tell you, because a shutter that cannot be raised in an outage is a real problem.

Does it come with a remote and controls? No. The motor is supplied on its own. Control panel, push button station, receiver, handsets and safety devices are ordered separately and quoted together.

Price: OMR 166.000. In stock. Installation quoted after we see the shutter height, shaft size and a photograph inside the box.