How to match the right generator to the pump?

How to match the right generator to the pump?

In modern industry and life, pumps play an indispensable role. Whether in agricultural irrigation, construction, sewage treatment or industrial production, pumps play an important role. As the power source of the pump, the rationality of the selection of the generator is directly related to the operating efficiency and stability of the pump.

There are two ways to power the pump. One is that the motor is directly connected to the pump, and the other is that the diesel engine or gasoline engine is connected to the pump head to power the pump.

Indoors, the motor is generally directly connected, and if it is outdoors, it is generally directly connected to the diesel engine. If you use a water pump connected to the motor outdoors, you need to equip it with a generator set. Outdoors, this motor has no electricity to plug in, so a generator set is needed to generate electricity and transmit it to the motor. The motor then drives the pump to use.

Different types of pumps have different requirements for generators. For example, small household pumps usually only need a smaller power generator to meet the needs, while large industrial pumps require high-power and high-reliability generators. In addition, different working environments and usage conditions will also affect the choice of generators. For example, when working in the field, you may need to choose a generator that is portable and adaptable to harsh environments; when using it in fixed places such as factories, you can choose a fixed generator with greater power and better stability.

Therefore, when equipping a pump with a generator, you need to comprehensively consider factors such as the pump's power requirements, working environment, and usage conditions to select the most suitable generator. Next, we will introduce in detail how to choose a suitable generator for a pump from different aspects.

(Ⅰ）Determine the power of the pump

1. First, match the required pump model according to the required pump flow head, and determine the power required by the pump (usually in kilowatts, kW), which is the power required by the pump under normal operating conditions. For example, the nameplate rated power of a centrifugal pump is 5kW, which is the basic power required for its stable operation.

2. Consider the starting current

Many pumps require a large current at the moment of starting, such as multi-stage pumps, and this starting current may be several times the rated current. Take a 7.5KW motor as an example. Its starting current multiple is generally 6.5 times the rated current. The rated current of a 15KW generator is 15000/380/1.732/0.8 = 28A. The time allowed for a generator overload of 3.5 times is 15S, which is enough for the motor to start. For a 150KW water pump, the starting current will also be much greater than the current during normal operation. Therefore, when selecting a generator, make sure it can withstand the additional load at start-up. Generally, it is acceptable to use 3 to 5 times the rated current of the motor as the average starting current value. For common 220V single-phase motors, the rated current is estimated at 5 amps per kilowatt and 2 amps per kilowatt for 380V three-phase motors, and then multiply it by 3 to 5 as the starting current.

(Ⅱ） Select the power of the generator

1. Calculate the minimum power of the generator

The power (kW) of the generator should be greater than the product of the rated power of the pump and the starting multiple. Assuming that the rated power of the pump is P (kW) and the starting multiple is k (such as the starting multiple of the asynchronous motor mentioned above is 4 - 7), the generator power should be at least P×k. For example, for that 5kW centrifugal pump, if the starting multiple is 6, the generator power should be at least 5×6 = 30kW.

2. Consider power redundancy

In order to cope with some special situations, such as power grid fluctuations, slight overload of the pump, etc., it is recommended to add a certain amount of redundant power on the basis of the calculated minimum power. Generally, the redundancy coefficient can be 1.1 - 1.3. According to the previous example, if the redundancy coefficient is 1.2, the appropriate power of the generator should be 30×1.2 = 36kW.

(Ⅲ） Match the voltage and frequency of the generator

1. Voltage matching

The rated voltage (such as 380V, 220V, etc.) will be marked on the motor nameplate of the pump, and the output voltage of the generator must match the rated voltage of the pump motor. If the voltage does not match, the motor may not work properly or even be damaged. For example, if the rated voltage of the pump motor is 380V, you need to choose a generator with an output voltage of 380V.

2. Frequency matching

1. In most countries such as China, the standard frequency of the power grid is 50Hz. Pump motors are usually designed according to this standard frequency, so the output frequency of the generator should also be 50Hz to ensure that the pump motor can operate normally. Otherwise, the frequency mismatch will affect the speed and output power of the motor and reduce the working efficiency of the pump.

(Ⅳ） Consider other factors

Environmental factors

1. If the pump and generator work in harsh environmental conditions, such as high temperature, high humidity, sand and dust, etc., it is necessary to select a generator with a corresponding protection level. For example, for generators used at the seaside, the performance of anti-salt spray corrosion should be considered to ensure that the generator can work stably and reliably and provide continuous power for the pump.

2. The speed of the pump and the speed of the generator should match. If they do not match, how to equip a reducer to solve the problem?

HUATAO GROUP has a strict quality control system and rich production experience in pumps. The motors can be supplied by a full range of brands, including Cummins, Perkins, Weichai, Yuchai, etc. The technicians are experienced and can provide high-quality products. Moreover, the after-sales service network is relatively sound, and technical support and maintenance services can be provided in time when problems arise, reducing downtime and losses. Please contact us if you have any needs.