Frequently Asked Questions

• Our geared motors and gear units, with the exception of electric motors, are covered by a two-year warranty. For motor warranty please refer to the electric motor manufacturer’s manual or warranty certificate. This warranty is valid only if the gearbox is installed and operated according to our operating instructions and is used under the permissible conditions for the appropriate gearbox type as stated in our catalogue. Gearbox parts made to order according to customer specifications are not covered by this warranty.

• The warranty period starts from the time of commissioning as stated on the warranty certificate and last for two years. If the commissioning time is more than three months after the billing time, the total warranty time is limited to 27 months starting from billing time. If the warranty certificate is not submitted to our company after commissioning, the total warranty time will be limited to 24 months after the billing time.

• Any time required for maintenance, repair or replacement during the warranty period will be added to the warranty time. This time starts from the date on which the company or representative was made aware of the problem and ends on the date of recommissioning.

• If the product fails to operate because of a manufacturing or assembly fault during the warranty period, the product will be repaired free of charge.

• If the product fails to operate because of a manufacturing or assembly fault during the warranty period and cannot be repaired, the product will be replaced with a new one according to the report from our service department stating that the defect cannot be repaired.

• Customers must inform the manufacturer of any problems after the service and repair of the failed product.

• The warranty does not cover consequential costs resulting from downtimes, physical or mental injuries etc. incurred by the customer, except for the product itself.

• If you can't download your products technical drawings, please contact us at [email protected]

• The main factor affecting delivery time is the order of additional accessories for the standard products, as we receive these accessories from third-party suppliers. For a faster delivery you can order your gearbox after viewing the stock status of your unit on the Internet.

• If you calculate your applications load spectrum in detail, you can select gearboxes with a service factor of less than one, but we do not recommend gearboxes with a service factor of less than 0.8.

• The gearbox mounting position is important because it is affects the oil level in the unit. Some mounting positions require the use of additional accessories for effective lubrication of gears and bearings in the gear unit (expansion tank, pump, etc.). It is therefore important to let us know the mounting position when placing your order.

• Usually there is no specific type of gearbox for required for any specific application, but some of our gearboxes are industry-specific, for example V series hoist drum drives, HTE, KRE and DRE extruder drives, and NRB agitator drives. P series planetary gearboxes are often used for mobile applications. When selecting gearbox for your general industrial application you must consider their mounting position and your machine. You can choose a suitable gearbox with the help of the information in our catalogues and tutorials. For further information and assistance, contact our sales representatives.

• This means that your order has not been confirmed yet. Please contact your sales representative for additional information.

• Use the technical data in our catalogue to determine whether cooling is required for your application. Especially for H, B and P types you may have to use additional cooling.

• The main factors are:

• Daily working hours

• Load class

• Start / Stop cycles per hour

• Motor type driving your gear unit.

• Other factors

• After calculating the service factor for your gearbox, you must consider other factors, such as radial load and thermal power etc...

• You must choose the oil type for your gearbox carefully considering the ambient and working conditions of your machine. Never mix different types of oil as this can damage your gearbox.

• Your gearbox’s surface temperature can be around 70 – 80 °C. You cannot touch surfaces with this temperature with your bare hands. Especially worm gearboxes, extruder type gearboxes and planet gearboxes have high working temperatures.

• Login credentials for the GST program are provided by Yılmaz Redüktör. We offer two different user profiles: Distributor and Corporate Company. Corporate companies can select their distributors and request quotations through the GST system.

• Monoblock housings which have a high rigidity

• Wide range of products

• Price advantages compared to competitor products

• Grinded and hardened gears

• Order tracking through internet

• Housings, gears and shafts are all made in two of Yilmaz Reduktor’s factories in Turkey. Seals and bearings are manufactured by our suppliers in Europe.

• Irreversible gear units cannot be driven from their output shaft. Some worm gearboxes are irreversible. It is determined by the load and lead angle of the gear units’ worm.

• The required motor rating depends on the driven machine. The gearbox’s drive torque must be higher than the torque required by the machine. The machine manufacturer is responsible for calculating the required machine power. For some basic applications you can calculate the required power approximately with the help of programs available in the GST module on our website.

• 4 different losses determine the efficiency in Gearboxes

• Churning losses

• Gear mesh losses

• Bearing losses

• Sealing losses

• In gearboxes with helical or bevel gears, these four losses cause about 2% efficiency loss in a single stage. With n stage approximate efficiency is 0,98^n. For example 3 stage gearbox efficiency is 0,98*0,98*0,98= 0,94

• Output torques in our catalogues are calculated taking into account all these power losses.

• Gear quality is measured; involute, helix angle and gear pitch values compatibility with the defined values in DIN3961 standard. There are 12 quality values between 1 and 12 in DIN3961. Grade 1 represents the highest quality, while Grade 12 represents the lowest quality.

• Gears in industrial gearboxes require 6. Quality. All of our produced gears are sixth and upper quality gears with the help of high technology CNC machines.

• Worms are produced from case hardened steel (21NiCrMo2) and worm wheels are produced from bronze alloys (Gz12SnCuNi)

• The efficiency in worm gearboxes are low because of sliding power transmission mechanism, because of that chosen materials friction coefficient between each other have to be low and their strength have to be high.

• The friction coefficient between steel and bronze is much lower than between steel and steel or between steel and cast iron. With the help of chosen material types efficiency is higher.

• Cast iron (GG20-22) and nodular cast iron (GGG40) housings and flanges are produced according to sand casting. Molding process is done with automatic machines. Aluminium parts are produced with aluminum injection method.

• Gearboxes are controlled in all production steps

• After raw material is supplied; material spectral analysis and tensile test

• After casting process; spectral analysis

• After hardening process; hardness and hardness depth measurement

• 3D measurements of gears and housings

• In final control; output speed measurements, electrical motor voltage and current measurements

• Our general factory production is according to ISO9001 and all parts in gearboxes have different norms to follow while producing; for example keyway norm is DIN6885 and tapped center holes are according to DIN332.

• In planetary and worm gearboxes we are using synthetical oils and in helical and bevel gearboxes we are using mineral oils. Changing interval for synthetic oils is 20000 hours and for mineral oils 10000 hours.

• Synthetic oils are preferred for compact and low efficient gearboxes because viscosity index for synthetic oils is higher then mineral oils. With the help of that synthetic oils viscosity are higher at high temperature degrees.

• Helical gears contact ratio is higher then spur gears; with the help of this they can withstand much higher torques and they work silently.