M-TEK (www.mtek.co.za) is a small, but dynamic, Centurion-based company, which for many years has specialised in the manufacture of slip rings. Slip rings, of course, are electrical conductors designed to carry current (for power) or signals from a stationary wire into a rotating device such as an armoured vehicle turret.
M-TEK specialises in compact, instrumentation type slip ring assemblies designed to carry DC and AC power, digital or analog data together with control and video signals.
M-TEK was started in 1980 as Groenewald and Zimmerman, named after its founders, Danie Groenewald and the late Ulrich Zimmerman. The company was renamed M-TEK in 1980 and Danie Groenewald is the managing director.
In order to achieve the lowest possible electrical noise levels, gold alloy wipers sliding onto hard silver-plated rings are utilised. For power, copper alloy rings with carbon brushes are used. M-TEK produces a large range of slip ring assemblies and over the years these have been used for periscopes, sighting systems, aerial observation platforms, optronic and radar positioners, winch reels, cranes and so on. The slip rings used on the Reutech Radar optronic and radar scanner on the new corvettes were manufactured by M-TEK. While the company produces a large range of standard products, a speciality is providing custom slip ring assemblies to meet the exact requirements of customers.
As an example of the standard product range, its C-Series slip rings are a selection of robustly well-sealed housed slip ring assemblies coming in standard lengths, containing from 10 to 40 separate circuits and intermediate lengths. The H-Series slip ring is a housed, self-contained slip ring assembly, and is frequently used for airborne optronic positioners. This slip ring has 140 separate circuits in its longest version. The company's standard slip ring assemblies are qualified to work under extreme temperatures in the -20 to +55°C range. Note that very high rotational speed causes unacceptably high levels of contact resistance and the preferred maximum tangential velocity is 0,5 m/s using gold alloy brushes sliding in hard gold-plated V-grooves.
Besides slip rings, M-TEK also produces a range of servo actuators, which are made to order to meet the customer requirements. These servo actuators are either directly driven by permanent magnet, brushless DC motors, or via a low backlash gear arrangement. The torque range available from existing designs varies from 5 Nm at 10 rpm to 1500 Nm at 60 rpm. Typical applications include a geared hollow shaft actuator with angle sensor and slip ring included and electro-mechanical replacements for hydraulic servo actuators.
Along with servo actuators M-TEK positioners are used for accurate positioning of optronic observation equipment and/or radar antennas for applications on land, sea and air platforms. Positioners are supplied for single, dual and four-axis applications (the latter is used in ATE's UAV platform). M-TEK uses brushless DC motors with resolver feedback. The two and four axis positioners are used in conjunction with gyros for inertial stabilisation.
M-TEK also offers a tilt measurement system which accurately measures two orthogonal tilts (such as pitch and roll) from one sensor (a dual-axis inclinometer). If three sensors are suitably placed, then the tilt of the rotation angle of a rotating system such as a tracker or a gun can be measured relative to a master datum, or with respect to another gun or tracker.
M-TEK also offers a range of angle sensors, which again, are non-stock items, but are based on the company's proven technology, being tailored to the customer's specification. The angle sensors use resolver technology and are typically capable of an angular accuracy of 40 arc seconds over 360°. Higher accuracy is possible and these devices can be designed accordingly.
Another popular product from M-TEK is its range of hand controllers for armoured vehicles, and the company offers versions which use both hands (eg, its armoured vehicle hand controllers) or single hand (eg, stiff-stick handgrip). Once again, these products are based on proven and well-used designs, but the final product will match the customer specifications. The hand controller output signals are typically generated by potentiometers, strain gauges or inductive sensors. They have been proven to operate in high shock and vibration environments and analog outputs as well as several digital bus interfaces are available.
Applications of M-TEK's in-house capabilities include the building of surveillance platforms, electro-optical tracking systems and for the SA Navy, electro-optical-radar tracking systems. M-TEK is also responsible for the stabilised sights fitted to the ATE Vulture and this business will expand when the former company enters the surveillance UAV market. Here M-TEK will probably have to integrate infrared systems into the sight, whereas the Vulture makes use of a standard visible CCD camera. Over the years M-Tek has designed and produced a variety of elevation-over-azimuth tracker positioners and pedestals with appropriate electronics and control software.
M-TEK at one time was more deeply involved with optronics and in 1991, in partnership with the Optical Sciences Division of the CSIR it developed the country's (if not the world's) first electronic zoom lens (the El-Cam) which was used by anti-aircraft guns to track and centre the boresight, on fast moving aircraft. In evaluations carried out at that time the system performed excellently. While those at CSIR thought its own mechanical system was pretty good, M-TEK redesigned everything and showed it how to engineer such a precision product.
Another M-TEK product is odometers used to provide quadrature input pulses to ground vehicle navigation systems. M-TEK odometers are fitted directly to any engine gearbox or to the inside of a vehicle hub or wheel. The odometer provides two sets of square waves, 90° phase-shifted with the signal being compatible with RS232. The number of pulses used per revolution depends on the application.
M-TEK works closely with a number of local defence companies, including Reutech Radar and ATE. While its main business is still in this country it also exports a not insignificant number of its products.
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