Leybold vacuum pumps (SV40 BI FC, SV65 BI FC) trip circuit breakers - WKB99643

SYMPTOMS

• Laboratory power circuit breakers trip when Leybold SV40 BI FC or SV65 BI FC vacuum pump is connected to a power socket

• Backing pump power cable fuse can also sometimes be damaged

ENVIRONMENT

• European 230V mains supply
• SQD2
• SYNAPT G2-S
• SYNAPT G2-Si
• Xevo G2-S QTof
• Xevo G2-S Tof
• Xevo G2-XS
• Xevo TQ-S
• Xevo TQ-S micro
• Xevo TQD

CAUSE

A large inrush of current can occur as the capacitor in the pump charges, even when the pump is switched off. This inrush can be large enough to trip a type B or even a type C breaker.

Very low mains impedance (a short cable from the mains distribution unit) increases the chance of nuisance tripping. 

Tripping is most likely when the pumps are connected to the main supply after a period of inactivity.

This effect does not indicate a fault with the pump.　

FIX or WORKAROUND

1. Reset the breaker - it may take several attempts.
2. Be aware when setting up an instrument that the vacuum pump should be on its own breaker and must not share a line with sensitive equipment that is at risk of damage or significant downtime from a loss of power (for example, Tof instruments or systems acquiring data).

ADDITIONAL INFORMATION

The amount of current drawn when connecting the pump depends on the laboratory supply characteristics, and nuisance tripping of circuit breakers does not occur at the majority of sites. Where it does occur, the breaker should be reset and the pump connected again—this step may need to be repeated a number of times until the capacitor is sufficiently charged. During a power cut, the capacitor will discharge, so nuisance tripping can also occur when power is restored.　

Using a 5-meter mains lead (with 16A IEC C19 connector) that is wound into a coil of up to 15 cm in diameter and secured with cable ties can help reduce nuisance tripping. Such cables are readily available at shops that sell computer uninterruptible power supply systems (UPS).