KNOW-HOW

What does the IP protection class mean?

The IP protection class indicates the extent to which the casing is protected against the ingress of foreign objects (e. .g. dust) and water. The IP protection class consists of two digits: the first describes protection against contact and foreign bodies, whilst the second describes protection against moisture and water. The IP protection class in accordance with DIN EN 60529 thus indicates how dust- and water-tight a casing is. For more information, see:  https://en.wikipedia.org/wiki/IP_Code.

The LP chain hoists are rated to IP65 and are therefore dust-tight (6) and protected against water jets (5). They are ideal for outdoor use – even under demanding conditions.

What is the difference between electric chain hoists and motors?

There is no technical difference. In industry, the term ‘electric chain hoist’ is usually used, whilst in the entertainment and events sector, the term ‘motors’ is often used. Both terms refer to the same device: an electrically powered mechanism for raising and lowering loads.

Can GIS electric chain hoists be used outdoors?

Yes, electric chain hoists with a protection class IP 65 can be used outdoors. The GIS chain hoists in the LP / LPM series come as standard with a protection class IP 65, which means that the chain hoist is dust-tight and protected against water jets. This ensures reliable operation outdoors. The permissible temperature range for outdoor applications is between -15 °C and +50 °C. Suitable options are available for applications outside this range.

What are the advantages of profile-steel chains?

Profile-steel chains, such as those used in the LPM and LP electric chain hoists, offer approximately 15 per cent more capacity for the same nominal diameter compared with a round-steel chain. The larger cross-sectional area therefore has a positive effect on the load-bearing capacity.
Furthermore, chain wear is noticeably reduced with profile-steel chains, which significantly extends the chain’s service lifetime.

What load capacities are single-phase electric chain hoists suitable for?

GIS single-phase electric chain hoists are suitable for loads of up to 2,000 kg. At maximum load, the lifting speed is reduced to 2 m/min to ensure a safe and controlled lifting operation. Matching single-phase motorised trolleys are available.

What is the temperature range for the use of electric chain hoists?

GIS electric chain hoists are designed in their standard version for a temperature range of -15° to 50° C. Special versions are used for ambient temperatures outside this standard range.

What is a D8 motor?

A D8 motor is a common industrial chain hoist used in stage technology in accordance with the German IGVW standard SQP2:2024. When suspending loads above people, a secondary safety measure is required – for example, a sling chain or a wire rope sling rated for double the nominal load – to secure the load reliably.

GIS motors in the D8 version can be operated as climbing hoists or in a stationary configuration without modification, and cover load capacities of up to 4,000 kg in single-strand operation and up to 6,300 kg in double-strand operation. The LPML and LPL chain hoist series have been specially developed for rigging applications in the D8 range and comprise motors for load capacities of 500, 1,000 and 2,000 kg. Thanks to their very low weight, they are particularly suitable for open-air events and concert tours.

Important: A second brake can be retrofitted to GIS motors. However, this does not automatically result in the motor being classified as a D8 Plus motor.

What is a D8-Plus motor?

A D8-Plus motor is an electric chain hoist specifically designed to support loads above people. Typical applications include, for example, video cubes suspended above ice rinks or trusses carrying loudspeakers, LED screens and spotlights on and around concert stages. Unlike the D8 motor, a D8 Plus motor does not require an additional secondary safety device, as it already meets the necessary safety requirements.

The safety-related criteria in accordance with the German IGVW standard SQP2:2024 include a static chain safety factor of at least 8:1, twice the rated load capacity of all components in the force path, and the inclusion of a second brake.

GIS motors in D8 Plus version can be operated as climbing hoists or in stationary mode without modification and cover load capacities of up to 2,500 kg in single-strand operation and up to 3,200 kg in double-strand operation.

What is a C1 motor?

A C1 motor compliant with the German IGVW quality standard SQP2:2024 is used for supporting and moving loads above people, as is often the case in theatrical productions or stage shows. These applications are subject to particularly stringent safety requirements.

The mandatory criteria include:

- A dynamic chain safety factor of at least 8:1
- Double the rated load capacity of all components in the power transmission chain
- Fitting of a second brake
- Gearbox limit switches with additional emergency stop contacts
- Load-sensing pins for overload protection

Position measurement using an encoder is often required in addition, in order to precisely detect and monitor the position of the load hook.

GIS motors in the C1 version can be operated as travelling hoists or in stationary mode without modification and cover load capacities of up to 2,000 kg in single-strand operation and up to 2,500 kg in double-strand operation.

Is it permissible to suspend loads above people using entertainment chain hoists in industrial applications?

Whether it is permissible to suspend loads above people in industrial settings depends on whether the hoisting equipment used complies with the requirements of standard EN 14492-2, Annex E. This annex sets out the additional safety requirements for such applications. They meet the criteria for the D8 Plus version in accordance with SQP2 and must be fitted with a limit switch.

It should be noted that entertainment chain hoists are not automatically approved for industrial applications. For industrial use, it must be verified that the chain hoist in question fully meets the requirements of EN 14492-2, Annex E.

What is a group movement?

A group movement refers to the joint lifting and holding of a load – for example, a truss, a truss system or an LED cube – by several chain hoists. The lifting and lowering movements take place synchronously, ensuring that the load moves in a controlled and uniform manner.

The motors involved are controlled via a controller, such as a portable case, rack or wall-mounted control unit. From there, the lifting and lowering movements are initiated, and it is determined which chain hoists are involved in the group operation and which are not. The emergency stop button activates all connected motors.

Do all motors run at the same speed in a group movement?

Although all motors in a group movement operate at the same nominal stroke speed, in practice they do not run at exactly the same speed. There are several technical reasons for this: slight slippage in the drive, minimal differences in the stator windings, or an uneven distribution of the load. These factors lead to small speed variations between the motors, which are normal and to be expected in group runs.

What is meant by a stationary application of a chain hoist?

In a stationary application, the chain hoist is securely mounted to the ceiling or to an existing installation via its suspension component – either a suspension hook or a suspension eye – (motor up). The chain exit is located on the underside of the motor, and the load is suspended from the load hook attached to the chain. The load therefore moves exclusively along the vertical lifting axis of the fixed chain hoist.

What is a climbing hoist?

In a climbing hoist, the load hook is attached to the ceiling or to an existing installation so that the body of the chain hoist is at the bottom and the chain outlet is at the top (motor down). The motor therefore operates ‘upside down’. The load is attached to the hoist’s suspension point – usually a swivelling hook suspension. During lifting, the chain hoist, together with the attached load, is pulled up to the load hook.

Important: In this application, the weight of the motor itself, including the chain, must be deducted from the rated load capacity.

What is meant by the ‘low-voltage’ version?

In the low-voltage version, each motor is fitted with a transformer, a low-voltage contactor control (standard: 42 VAC) and a gearbox limit switch for the highest and lowest hook positions. These components enable the motor to operate safely at a low control voltage.

Two connection cables are required for operation: a power supply cable (1 m, red 4-pin CEE plug) and a control cable (1 m, yellow 4-pin CEE plug). Both cables lead to the controller, which issues the control commands and handles the emergency stop function for all connected motors.

What is meant by the ‘direct control’ version?

In the ‘direct control’ version, the motor contains neither a transformer nor a contactor control system, and in most cases no limit switch is integrated either. The motors are connected directly to a controller via a connection cable (1 m, red 4-pin CEE plug). The controller regulates the direction of travel by switching the phases. Motors in the direct-control version have a single lifting speed.

A limit switch is available as an option for direct-control stage chain hoists.

How does position measurement work in chain hoists?

Incremental or absolute encoders are used for position measurement in chain hoists. These encoders detect the rotational movement of a shaft or a wheel and, based on this, enable the distance travelled by the chain hoist or the load hook to be calculated. In the chain hoist, the encoders are mounted either on the sprocket or on the drive shaft. Depending on their installation location, they detect the movement of the sprocket or the drive shaft.

Distance measurement is mandatory for chain hoists compliant with C1 (UC4–6). The customer can specify whether the encoder must also comply with the SIL3 safety standard.

What is the difference between an incremental and an absolute encoder?

Either incremental or absolute encoders are used for position measurement in chain hoists. The difference lies in the way the position is determined and stored.

An incremental encoder counts the pulses per revolution during operation. To determine an absolute position, it must first be synchronised via a reference run after being switched on. After each power cut, it restarts from zero and determines the position solely on the basis of the newly counted pulses.

An absolute encoder, on the other hand, permanently stores its reference position. This means that the system already knows the current height of the load hook as soon as it is switched on, without the need for a reference run.

How does electronic load measurement work?

Electric chain hoists can be fitted with an electronic load measurement system as an option. This involves integrating a load cell or load-sensing bolt into the hoist’s suspension. These sensors detect the force being applied and send electrical signals to the evaluation or control system, which uses this data to calculate the current load weight.

The load measurement system does not necessarily have to be installed in the chain hoist itself. In stage construction, it is common practice to attach chain hoists with eye suspensions to shackles that have an integrated load measurement system.

If an overload is detected, the control system must immediately shut down all motors in a group. Thereafter, the hoist may only be operated in the lowering direction until the overload has been removed.

Is the transport of persons permissible?

No, the transport of persons using electric chain hoists is not permitted under EN 14492-2 or our operating instructions. These standards clearly define electric chain hoists as equipment for lifting loads, not persons.

However, the SQP2 and EN 17206 standards state that the decision and responsibility for transporting people lies with the organiser’s safety officer or the performer. These standards govern applications in the entertainment sector and, under certain conditions, permit so-called ‘performer flying’ applications, provided that the relevant safety requirements are fully met.

How does brake monitoring work for motors?

Motors can be fitted with brake monitoring as an option. To achieve this, the DC spring-loaded brakes used are fitted with an additional microswitch. This microswitch sends a signal to the control system, indicating whether the brake is released (active) or not. In this way, the control system can monitor whether the brake is operating correctly.

Depending on the applicable regulations, brake monitoring is mandatory for certain theatre installations and stage applications.

What is a safety load hook?

A safety load hook features a mechanically locked hook latch that reliably secures the load. The hook closes automatically under load and can only be unlocked manually when unloaded. Thanks to this design, it cannot open accidentally, thereby preventing the load from falling.

With a standard load hook, a hook safety catch prevents the load from falling out, but it is not locked. A safety load hook therefore offers a higher level of safety, particularly during dynamic lifting operations.

Tips & tricks: Lubrication the chain

Regular lubrication of the load chain can increase its service life by a factor of 20 to 50. The operating instructions recommend a low-viscosity gear oil of the 15W 40 type. The chain manufacturer also emphasises the importance of viscosity and recommends a value below ISO 300. An unsuitable oil can cause the chain to clump together in the chain bag, preventing the chain links from running smoothly through the chain guide. The load chain must be lubricated along its entire length, including between the chain links, before commissioning and regularly during use.

Tips & tricks: Preventing sideways pull

A load angle exceeding 4° should be avoided, as this places excessive strain on both the load chain and the chain guide. This leads to increased wear and tear and may compromise the operational safety of the system. Correct alignment of the hoist and the load ensures that the chain runs smoothly and that the components are not subjected to unnecessary stress.

Tips & Tricks: Incorrect running direction of the electric chain hoist

If the load is lowered when the ‘Up’ button is pressed, or vice versa, the electric chain hoist has most likely been incorrectly connected to the mains supply. In this case, the connection must be checked and correctly carried out by an authorised specialist to ensure fault-free operation.

Are trolleys equipped with a fall protection?

All GIS manual and electric trolleys are fitted with fall and climb protection made from solid cast steel. Among other things, this prevents trolleys from falling off the crane runway in the event of a roller breaking, the trolley tilting or strong lateral forces being applied. In addition, finger protection ensures that fingers cannot get caught between the steel girder and the rollers.

Can GIS trolleys manoeuvre around curve radii?

GIS trolleys of the GHF and GMF types can be fitted with support rollers to ensure smooth cornering. These enable the trolleys to negotiate defined curve radii safely and stably. The exact specifications regarding the possible radii are shown in the respective dimensional drawings for the trolleys.

Tips & Tricks: Trolley with plastic rollers

If the standard steel rollers are too noisy or if noise is carried into a building in a disruptive manner, trolleys with plastic rollers can be used. These are suitable for load capacities of up to 1,250 kg and significantly reduce noise levels. Our sales team will be happy to advise on further noise insulation solutions.

Tips & tricks: Trolley with stainless steel rollers

If the working environment contains aggressive acids or alkalis, we recommend using a corrosion-resistant electric chain hoist together with a trolley fitted with stainless steel rollers. This combination protects the components from chemical stress and ensures reliable operation even under demanding environmental conditions.