Automation technology combines mechanical and electrical engineering to form efficient systems and plants. Whether servo controllers, frequency inverters or inverters, the particularly impulse resistant power resistors of the Krah Group are specially designed for use as braking resistors or charging and discharging resistors. These resistors have proven themselves millions of times over allowing your handling systems, robots, conveyor belts and sorting systems to work trouble-free and safely.
Krah Group resistors are used in these application areas:
- Electric drives
- Conveyor belts
- Handling systems
- Robotic sorting plants
Power Resistors from the Krah Group continue to play a decisive role in the field of electrical energy technology, which details with electricity generating wind power, photovoltaics, transmission and conversion, and electrical energy storage; the latter is presently an increasingly frequent requirement. The special requirements such as high-voltage resistance, high energy absorption capacity or IP protection class are ideally met by the available resistance technologies. If a requirement cannot be mapped with the standard resistors, we will work with you to develop a suitable solution.
Krah Group resistors are your first choice for:
- Filter systems
- Photovoltaic systems
- UPS systems
- Wind power plants
- Heat pumps
Equipment and Plant Construction
The resistors of the Krah Group will undertake your tasks every day in an exemplary manner, whether as a reliable braking resistor in an elevator or as a reliable filter resistor in a medical device. Krah Group resistors are used worldwide in process technology systems, such as the chemical industry and on oil platforms where conditions can be very challenging.
Our quality specification, e.g. QSV and zero-defect strategy, offer you solutions for the challenges of equipment and plant construction:
- Stage technology
- Medical technology
- Process engineering
- Roll-up doors
- Escalators and elevators
The continuous and rapid development of power electronics, which has been going on for decades, also requires new solutions in the field of Power resistors. With a wide variety of resistor technologies, we will find within the Krah portfolio the suitable resistor for your DC link application, your load unit or your pre-charge or dis-charge task. For a performance increase designs with air-cooling, forced air-cooling as well as liquid-cooled versions are available for maximum power requirements.
As a reliable partner of the Krah Group we can offer customized resistor solutions for the following applications:
- Frequency inverters
- Servo controllers
Mechanical engineering is an exciting market segment in which designers are challenged to increase productivity, improve efficient or optimize precision. With the support of simulation programs, the Krah application engineers can also find the optimally dimensioned power resistor for your application in order to safely and reliably meet the requirements set as a brake, filter or charge and discharge resistor.
Krah Power resistors have proved themselves being used in:
- Production machines
- Welding technology
- Machine Tools
Transport and Logistics
A smooth supply of goods requires highly available systems and equipment, both in procurement and in production. The flow of goods is increasing and must arrive at their destination faster than ever. As a result, the demands on infrastructure is also increasing; e.g. higher speeds in conveyor systems require more efficient braking resistors. The particularly impulse-resistant power resistors of the Krah Group have been specially designed for use as braking, charging and discharging resistors.
Krah power resistors prove their worth every day in these systems:
- Dynamic storage systems
- E-stacking truck
- Conveyor belts
- Crane technology
- Railroad engineering
Within e-mobility, powerful electric motors are used with intelligent systems managing the exchange of energy between the drive and the battery. The inrush current during the precharging of DC-link capacitors is controlled by KRAH’s pre-charge resistors, which have been designed for high voltage requirements and are particularly impulse-load resistant. Contact us and we will accompany you in your project as a partner with automotive QSV standards and provide you with resistors according to the AEC Q-200 quality standard.
We offer solutions for:
- Pre- and discharging of intermediate circuit capacitors
- Voltage interruption and discharging in the event of a fault or crash
During braking operations of e-vehicles the regenerative behaviour of the electric motor generates energy which is recharged into the battery system. If the battery is already fully charged and can no longer absorb energy, the generated energy must be absorbed by other consumers. KRAH braking resistors are suitable for this purpose. The generated heat can then for instance be used to heat the vehicle interior.
We will be happy to advise you on solutions with air or liquid cooled power resistors which are ideally suited for electric or hybrid vehicles:
- Brake resistors for recuperation operation
- Brake resistors as electrical brakes
On Board Charger (OBS)
In charging the battery by an external power supply/ grid, many electrical vehicles (BEV, PHEV) from cars up to floor-borne vehicles include an integrated charging circuit, which also realizes the pre- and discharge function of the DC-linked capacities. In this matter KRAH offers solutions for pre- and discharge functions based on resistors, optional extended to modules with integrated pre- and discharge relays.
High Voltage Coolant Heater
The coolant circuit is linked to the passenger compartment for heating purpose. For a rapid heating-up, KRAH offers additional heaters with high power, which will be direct placed in the fluid coolant. The geometries of these tubular heaters can be designed to the customer needs.
Heating / Conditioning
For the blower speed control of fans in manual air conditioning systems (HVAC), multiple-step resistor solutions offer a very robust and approved technology. The KRAH Group is the world market leader in this segment and will always offer you the most suitable solution, such as wire-wound resistors on ceramic supports or plate style resistors.
Do you need electronic controllers for your automatic air conditioning system? We are happy to support you.
Electric fans are used for engine cooling in vehicles. Given the environmental conditions of such systems, resistor solutions for fan speed control with one or more steps are a very good choice. Typically wire wound resistors on ceramic carriers are used. The KRAH Group’s product range also includes other technologies such as open coil resistors or plate style resistors.
For the effective suppression of electromagnetic noise in vehicle ignition systems, the KRAH-Group offers a wide range of noise suppression resistors (NSR) with various terminals. The wire-wound resistor reduces electromagnetic interferences caused by high voltage pulses and sparks. Due to the wire winding, the resistor also contains inductance and capacitance. Within the alternating power circuit, the ohmic, inductive and capacitive values cause an impedance resulting in a high attenuation and thus noise suppression in important frequency ranges such as the AM or FM band. The prime influence on the required frequency ranges is the influence of inductance.
The KRAH suppression resistors guarantee excellent noise reduction. Let us convince you of our competence.