Improving The Mix
Meanwhile, Baginto AB bakery in Sweden has been able to upgrade its mixing and dough preparation equipment, improving productivity and flexibility with Lenze SMD and SMVector IP65 Inverter Drives. The highly compact SMD drives are ideal for retrofitting in existing panels at the bakery, whilst the IP65 rating of the SMVector drives enables them to be mounted directly to stainless steel surfaces without the cost and complexity of control cabinets. In addition wiring is greatly simplified as the drives can be mounted closer to the motors they control.
The recent investment means that many areas of the bakery are now controlled by Lenze adjustable speed drives. The conveyors and rollers on Baginto's biscuit production line are equipped with Lenze SMD drives. The compactness of these drives makes them ideal for these applications. Supplied as retrofit units, they are providing smooth torque operation and fine speed control where machines already have control cabinets: the cabinets themselves are stainless steel due to the hygiene requirements in food production industries.
The flour mixing and dough folding equipment at the bakery also now employ variable speed operation - benefiting both the consistency and quality of the product. At these stations, the drives had to satisfy a requirement to allow manual adjustments to the mix during production. This meant that they had to be both visible and accessible, and close to the machinery that is usually moved around as part of the production process.
The IP65 enclosed SMVector inverters provided the ideal solution. Their in-built levels of protection against contamination meant that they could be mounted directly to the mixer and the rollers, on to stainless steel frames, without the requirement for an additional cabinet with its attendant space requirements, additional wiring, and cost.
The SMVector drives are dust-tight, so the fine flour dust in the bakery atmosphere causes the drives no problem at all. In addition, the SMV drives are also rated against low pressure jets, from the frequent washdowns required in food production environments.
The combination of the two drive systems: Lenze SMD drives where space is limited, and SMVector drives where operational and environmental requirements meant that they were the only solution, which has worked excellently at Baginto. The bakery has been able to increase productivity and flexibility with minimum disruption, and more importantly without breaking the bank.
The SMVector range of inverter drives, is available for single-phase operation from 0.37kW to 2.2kW, and three-phase from 0.37kW to 22.0kW. The SMV range removes the cost and complexity from vector-based motor control, offering fast dynamic torque response, sophisticated auto tuning and impressive low speed operation from a compact, low cost and simple to use package. The SMV drive also offers ingress protection to IP65, allowing for outdoor use, operation in environments with atmospheric moisture present and protection from low pressure water jets. The SMV range is designed for use in small motor applications where dynamic speed and torque control are required, such as conveyors, food production, packaging lines and HVAC systems.
Dynamic braking is used when an overhauling load causes regeneration from the motor to occur, especially in situations where the required deceleration time to stop the motor cannot be achieved due to High Voltage nuisance tripping. Most Lenze-AC Tech DB circuits are rated for light-duty use only. The dynamic braking (DB) control circuit is connected to and monitors the fixed DC bus line. When the DC bus reaches 114% of the maximum tolerance, it triggers the chopper circuit in the dynamic brake. The DB circuit will be active whenever the voltage rises on the DC bus. This can occur while the drive is running, while it accelerates or decelerates or even when it is stopped.
Using dynamic braking allows a faster deceleration time of a high inertia load. However, fast deceleration of a high inertia load may sometimes cause regeneration and trip the drive into a High Voltage fault. To avoid this, a dynamic brake chopping circuit is switched on when the voltage levels exceed the rated tolerance and brake resistors dissipate the regenerated voltage as excess energy.