VARIABLE SPEED DRIVES

Got an under-performing servo motor?

Match motor speed to the work, and stop paying for the rest

A motor started direct-on-line runs at one speed whether the process needs it or not, and draws a heavy inrush current every time it starts. A variable speed drive controls the frequency supplied to the motor, so the pump, fan or conveyor runs at the speed the process actually calls for. On centrifugal loads that usually shows up quickly on the electricity bill, and the softer starts take mechanical stress off couplings, belts and bearings. Motion Tronic specifies, supplies, installs, commissions and repairs variable speed drives across South African industry.

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VSD brands we supply and repair

Motion Tronic are the sole agents of Southern Africa for Inovance and Baumüller, and we hold stock locally so you are not waiting on an international order. Our workshop also repairs and retrofits drives from most major manufacturers, including ABB, Siemens, Mitsubishi, Lenze, Yaskawa, SEW-Eurodrive, Invertek, WEG, Allen-Bradley, Kollmorgen and Berger Lahr.

Where a variable speed drive pays for itself

Pumps and fans are the clearest case: because flow varies with speed and power varies with the cube of it, a modest reduction in speed makes a disproportionate difference to energy drawn. Beyond pumping and ventilation, we fit drives to extruders, conveyors, winders and cooling towers where the benefit is process control rather than energy alone — holding a line speed, synchronising one section to another, or ramping a heavy load up without shocking the driveline. If you are weighing a drive against a direct-on-line starter, or deciding whether to convert an ageing DC system to AC, we can assess the application and tell you what is worth doing.

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Why partner with us?

Drives are supplied, installed, repaired and tested by the same team. Here is what that means in practice:

Laser cutting machine cutting metal with sparks

Specified for the application

We size the drive against the actual load, duty cycle and control signals rather than the motor plate alone, and handle installation and commissioning through to a running machine.

Warehouse staff member handling a parts box

Repaired to component level

When a drive fails we repair the board itself rather than replacing the unit, which is usually faster and cheaper than a replacement on a long lead time. Repairs carry a 12-month same-fault warranty.

Technician operating an HMI panel on a production line

Tested under load before it ships

Our in-house dyno unit lets us run a repaired or newly configured drive against a real load and prove it before it goes back to your plant, instead of finding the problem during your start-up.

What makes us unique?

Five things worth knowing about the way we handle variable speed drives:

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We are the sole agents of Southern Africa for Inovance and Baumüller drive technology.

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We hold drive stock locally, which keeps you off international lead times when a unit fails.

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We repair drives at component level instead of defaulting to a replacement unit.

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Every repaired drive can be proven on our dyno unit under load before it returns to site.

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We handle the whole job from specification and panel build through to commissioning on your plant.

Frequently asked questions

A few questions we are asked regularly about variable speed drives:

What is the difference between a VSD and a soft starter?

A soft starter only limits the inrush while the motor comes up to speed, then drops out and leaves the motor running at full speed. A variable speed drive keeps controlling frequency for as long as the motor runs, so it can hold any speed the process needs. If you only want to protect the driveline at start-up, a soft starter may be enough; if you want to control speed or save energy on a variable load, you need a drive.

Can a variable speed drive really reduce energy costs on a pump?

On a centrifugal pump or fan, yes, and often substantially, because power varies roughly with the cube of speed. Throttling a valve to reduce flow wastes the difference as pressure drop; slowing the pump does not. The size of the saving depends on how much of the time the system runs below full flow, which is what we look at when assessing an application.

Do you repair variable speed drives, or only supply new ones?

Both. Our electronics workshop repairs drives down to component level, which is normally quicker and less expensive than replacing a unit, particularly where the original is obsolete. Where a drive is genuinely beyond economic repair we will say so and quote a suitable replacement.

Can you replace an obsolete drive that the manufacturer no longer supports?

This is a large part of what we do. We retrofit current drive technology into existing machines, matching the control signals and mechanical interfaces so the rest of the machine does not have to change. See the retrofits page and our previous work for examples.

How quickly can you turn a drive repair around?

It depends on the fault and on parts availability, but we hold stock locally and offer a priority service where downtime is critical. Tell us the machine is down when you enquire and we will treat it accordingly.

Where are you located?

The Motion Tronic headquarters is located within Unit E2, 14 Henred Road, New Germany, KwaZulu-Natal, South Africa. Our postal address is P.O. BOX 2329, Pinetown, 3600. We support plants nationally and travel to site.